The rapid development of artificial intelligence has posed new and higher demands on computing systems. Electronic computing systems, represented by Graphics Processors Unit(GPU), adopt the von Neumann architecture, which results in frequent data migration and high energy consumption due to the separation of processors and memory. The parasitic capacitance in electronic computing systems also hinders further improvement in computing speed, making it unable to meet the needs of further development of artificial intelligence for high-speed and high-efficiency computing hardware. The rapid development of integrated photonic devices has provided a feasible solution for achieving high-speed and high-efficiency computing hardware. The tunable multivalued devices based on Mach-Zehnder interferometers are a major technological approach in constructing photonic intelligent accelerators. These devices have the advantages of wide bandwidth and temperature insensitivity, making them an excellent choice for photonic hardware accelerators. Phase-change materials have the characteristics of continuously adjustable refractive index and non-volatile retention. Combining phase-change materials with Mach-Zehnder interferometers can achieve non-volatile multivalued properties, providing a new device foundation for constructing photonic intelligent accelerators. In this paper, a non-volatile photonic multivalued device with an Indium Tin Oxides (ITO) microheater is designed based on the combination of phase-change materials and Mach-Zehnder interferometer modulators. First, the structure of the photonic multivalued device is designed. Sb₂Se₃ is chosen as the phase-change material, and ITO is selected as the microheater material. The Sb₂Se₃ is deposited on one arm of the Mach-Zehnder interferometers waveguide, and ITO is deposited on top of the Sb₂Se₃. Cr/Au is deposited at the edge of the ITO to form electrodes. When the state of Sb₂Se₃ changes, it affects the phase of the transmitted light on the Mach-Zehnder interferometers waveguide, thereby changing the output of the Mach-Zehnder interferometers. This scheme has the advantages of faster modulation speed and higher modulation precision, enabling state transitions of the device to be achieved in milliseconds. The thermal distribution of the microheater has an important influence on the phase transition of the phase-change material. Two different microheater structures are designed and simulated using COMSOL software, including a square-shaped ITO and a structure with wider edges and a narrower middle. Through electrical-thermal simulations, it is found that the second structure can concentrate the generated heat more effectively and improve the efficiency of the microheater. Furthermore, the length and thickness parameters of Sb₂Se₃ are optimized through simulations in Lumerical software. Lengths ranging from 20 μm to 50 μm and thicknesses ranging from 10 nm to 40 nm are chosen. Finally, a length of 30 μm and a thickness of 30nm are determined as the optimal parameters for Sb₂Se₃, which maximize the modulation window of the device. The device is fabricated using processes such as photolithography, magnetron sputtering, and inductively coupled plasma etching. During the testing process, electrical pulses are applied to the microheater, with a pulse width of 1ms and an amplitude of 13.4 V. The tests demonstrate that the device achieves multivalued modulation with over 32 states (5 bits) during the application of electrical pulses. Several states are also selected for the retention characteristic tests, which show that the device can maintain stable states for up to 20 minutes, indicating good non-volatility. Finally, the spectral characteristics of the photonic multivalued device are tested to determine its bandwidth. The tests show that the output of the device remains stable between 1 540 nm and 1 580 nm, indicating certain broadband characteristics and providing a foundation for parallel computing. This electrically modulated non-volatile photonic multivalued device serves as a fundamental unit for large-scale non-volatile reconfigurable photonic hardware neural networks. In the future, the performance of this device can be further improved by exploring new microheater designs, aiming for lower power consumption and more adjustable states in photonic multivalued devices.