Ultrasonic ranging is a non-contact measurement method that is widely used in industry and transportation. In order to improve the ranging range of ultrasonic waves and solve the problem of crosstalk noise when the distance between multiple channels is relatively close, applies “ dual one-way pseudorange measurement technology” to the premise of changing the electroacoustic converter and transmitting and receiving hardware circuits. In the ultrasonic ranging system, the dual one-way measurement replaces the traditional reflective two-way ranging, and the clock between the ranging main end and the ranging slave is synchronized by the wireless serial communication to improve the ranging range, and the technology can also eliminate the system itself. Clock synchronization error. At the same time, the “time division multiplexing” technology is applied to perform time slot allocation through radio signal broadcasting, so that only one path in the ranging channel at any time is in a working state, and multi-channel close-range crosstalk-free measurement is realized. The experimental results show that the dual one-way measurement can more than double the reflection ranging range, and the detection accuracy is better than 1%. The reference of the time division multiplexing technique enables measurement of crosstalk without interference in ultrasonic multi-channel short-range channel spacing.