In order to decrease the design complexity of software and to enhance the control stability and accuracy of distributed feedback laser′s emitting wavelength, a temperature controller for semiconductor laser used in gas detection was developed, which includes digital signal processor, temperature setting circuit, temperature sampling circuit, analog proportionintegrationdifferential circuit, thermal electric colling control circuit, etc. A wavelengthtunable distributed feedback laser centered at 1 860 nm used for humidity detection was driven using the proposed temperature controller. Experimental results indicate that, the control scale on temperature is 10 ℃~50 ℃, the accuracy is ±0.05 ℃, and the temperatureestablished time is less than 60 s; with different driving current and temperature supplied by the system, the operation wavelength of the laser shows good tuning characteristics; the four spectral curves from four days′ measurements almost coincide with each other, demonstrating stable performances of the controller.