The transmitting device and the receiving device in the handheld laser range finder system have temperature-sensitive characteristics and are all low-power devices. When the precision temperature measuring circuit adopts Pt resistance, the self-heating effect of the Pt resistance affects the temperature measurement accuracy, which is generated by the self-heating effect of laughter. Based on the analysis of the temperature error of Pt resistance, a new pulse current power supply scheme is proposed. The pulse current supply circuit and its mathematical model of self-heating temperature rise process are established. The pulse width and The relationship of heat accumulation and the temperature measurement error caused by the self-heating effect are greatly reduced by reasonable control of the pulse width. The nonlinearity of Pt resistance is compensated by high-order orthogonal polynomial fitting method. The comparison between the measurement data of the temperature measurement module of the system and the temperature of the first-class standard platinum resistance is given. The temperature measurement system is used at different temperature points. The maximum error is 0.0006 °C. The system stability test results show that the control stability of each temperature point is better than 0.005 °C at 0~15 °C, which meets the needs of high precision laser ranging.