For the problem of large amounts of correlation calculation during indoor ultrasonic location based on CDMA , an improved indoor ultrasonic location method based on the combination of Code Division Multiple Access (CDMA)-Time Division Multiple Access (TDMA) was proposed in this work. The CDMA coding ultrasonic signals were emitted through TDMA technology, and the position messages of the unknown target can be calculated by the way of Time Difference of Arrival (TDOA) ranging algorithm. The ultrasonic signals of four beacons are transmitted and received in two different time periods in the MATLAB simulation experiment . The simulation results show that the improved indoor ultrasonic location method based on the combination of CDMA-TDMA can identify the beacons node effectively , At the same time , it can reduce the amount of calculation compared with the algorithm of the ultrasonic positioning based on CDMA .