A compact reconfigurable optical filter based on silicon-on-insulator with large bandwidth tuning capability is designed in this paper. The device is based on triple-ring-assisted Mach-Zehnder interferometer. The bandwidth and center wavelength of the device can be tuned at the same time by reasonably changing the phases of the microring resonators through the thermo-optic effect of silicon. The performance of the proposed device is simulated by finite difference time domain method. The simulation results show that the tuning range of the bandwidth is 1.4 nm to 10.6 nm， which accounts for 11.5% to 85% of the free spectrum range. The stopband extinction ratio is greater than 20 dB， and the passband loss is 0.4 dB to 0.7 dB， the footprint of the device is about 40 μm×60 μm.