In the traditional DS/FH spread spectrum system,the high power interference problem caused by transmitted signal makes the normal reception impossible.This problem is effectively solved by introducing time hopping to build DS/FH/TH spread spectrum system。At the same time,this paper focus on synchronization acquisition method based on decoding method,theoretical analysis of synchronization performance is made,such as false alarm probability,detection probability,mean acquisition time,etc. ,and computer simulation is introduced to prove the system’s effectivity .Compared with traditional correlation method,the decoding method has better performance in anti-interference and synchronization.