Abstract: This paper uses OFDM system model and synchronization technology as the entry point to carry on the research of timing synchronization algorithm of OFDM systems based on training sequence. Due to the drawbacks of timing estimation algorithm which based on the training sequence frame structure of SC algorithm has a peak plateau in timing estimation, timing position ambiguity and can’t make a precise time estimation, this paper presents an improved training sequence frame structure and algorithm based on SC algorithm. This paper improves the repetitive structure of the first part and the second part in the training sequence structure of SC algorithm. The improved training sequence frame structure uses Centro-symmetric structure of the first part and the second part. The improved algorithm doesn’t use the second part of the training sequence of SC algorithm to define the energy function, while uses the whole part of the improved training sequence to define the energy function. And then establishes a timing metric function and finds the best timing synchronization point to finish timing synchronization. Both the theory analysis and the results of simulation show that timing position ambiguity and imprecise timing synchronization of SC algorithm can be solved by the improved algorithm. The improved algorithm can ensure the precision of timing synchronization.