The work aims to solve the problems of low ranging accuracy and poor anti-interference in the traditional logistics industry robot obstacle avoidance system. A high precision ultrasonic ranging system based on DSP temperature compensation and wavelet threshold noise filtering was proposed, including the minimum system of DSP, ultrasonic sensor, LCD display module, temperature compensation circuit and alarm circuit. The ultrasonic ranging system corrected the sound velocity by collecting the ambient temperature in real time, and used the wavelet threshold transform algorithm to process the echo signal, which improved the signal-to-noise ratio and the starting point sharpness of the echo signal. CCS4.2 software and DSP chip were used for debug and experiment. The experiment showed that within the distance of 0~1200 mm, the measurement error of the system was ±4 mm. Wavelet threshold transform algorithm and temperature compensation circuit are used to improve the ranging accuracy of traditional logistics robot obstacle avoidance system.