A semiconductor laser temperature control system with board-level multi-channel is developed to control the temperature of multiple semiconductor lasers simultaneously in the detection of mixed gas. The system consists of multi-channel temperature acquisition module, digital signal processor module, thermoelectric cooler (TEC) and TEC control modules. The round-robin scheduling algorithm and integration-separated digital proportional integral differential algorithm are used to precisely control the temperature of multiple semiconductor lasers in real time. Temperatures of both the wavelength-tunable distributed feedback lasers centered at 1.65 μm and 1.56 μm are controlled when we use the proposed system. The temperature control experiment is carried out, and the luminescent spectra of the two lasers are detected. Results show that the system can control the temperatures of the two lasers simultaneously. The accuracy of this system can reach -0.011-0.015 ℃ and the response time is less than 3 s. The stability of the temperature controller is tested. The temperatures of the two lasers can stay stable after operation for 6 h, and the emitting peak wavelengths are stable in spectrum test for 10 h. For its tiny size, low cost, capability to be integrated, great stability as well as reliability, the temperature control system has great application prospect in mixed gas detection.