High-precision sensing is one of the basic capabilities of 6G mobile communication system to fulfill the demands of many application scenarios in the future, and the integrated design of communication and sensing is an important direction of 6G research. The multi-target sensing algorithm in the integrated design of sensing and communication in 6G mobile communication system was studied. First, three classic sensing algorithms were introduced that could achieve multi-target ranging and speed measurement and the algorithms were analyzed from three aspects: sensing accuracy, communication performance and computational complexity. It is shown that the optimal sensing accuracy, sensing capacity and communication rate could not be achieved at the same time by using either one algorithm. Second, combined with the characteristics of different sensing algorithms, an adaptive sensing algorithm was proposed that the receiver selected the appropriate sensing algorithm according to the measured signal-to-interference ratio to realize the joint optimization of sensing and communication performance. Finally, the link-level simulation was carried out to verify that the proposed algorithm can obtain better perception accuracy and communication capacity than any single algorithm.