The accuracy of traditional optical power acquisition instruments is not high, so they are unable to show the change of the optical power clearly in short term during the experiment, while data collection system for collecting voltage can be a good solution to this problem. On the basis of introducing working principle of 1 310 nm SLD light source, a driving circuit was designed, which can make SLD operate steadily by controlling current under the condition with a constant temperature. With the theoretical analysis and experimental verification, a new method of monitoring SLD output optical power by its voltage drop was provided, then true and reliable experimental data were obtained. From the driving experiment for SLD, it has proved that the output power has a certain relationship with driving current and voltage, and results show that the output power has a good linear relationship with the current, a good positive correlation index with the voltage. Taking advantage of collected voltage to monitor SLDoutput light power can greatly improve the test precision and data resolution, at the same time provides new electrical parameters for the SLD degenerate life test.