According to the demand of a high precision optical fiber gyro for the light source′s stability, the digital thermal control scheme for an erbium-doped super fiber source(SFS) was proposed based on the 32-bit digital signal processor TMS320F2812. By taking the erbium-doped SFS as the study object, the advantages and disadvantages of the existing light source temperature control technologies were analyzed, and the program of the "numeric constant current source + digital thermostat" method was developed according to the analog control scheme. The operating characteristics of a Thermo Electric Cooler (TEC), the internal structure and heat transfer mechanism of the SFS pump source were studied, and a mathematical model of the die temperature control system of the SFS light was established. Furthermore, a corresponding continuous domain lead-lag correction network was designed, the controller was discretized and a PID digital compensation control algorithm was realized. Finally, the control precision of the digital temperature control system for the SFS light source was verified experimentally. Obtained results show the precision is better than ± 0.05 ℃ in 20-90 ℃ and meets the requirements of optical fiber gyros for low power consumption and miniaturization.