The objective of this study is to make the genetic analysis and origin of sweet potato (Ipomoea batatas (L.) Lam.) by using sequence-related amplified polymorphism (SRAP) markers. 129 sweet potato accessions including wild relatives, landraces and cultivars were used. The phylogenetic trees of sweet potato and its wild relatives were constructed by MEGA and DPS softwares, and the genetic distance of sweet potato accession was calculated. The results showed that: (1) the average genetic distance of 124 cultivars and 5 wild relatives was 0.1848 and 0.4822, respectively. (2) The wild relatives were separated from cultivars at the level of L1=0.31, and 124 cultivars were classified into 8 different groups at the level of L2=0.21. (3) 129 sweet potato accessions were placed into 3 groups (I, II and III) on the SRAP constructed phylogenetic tree. Group I included 5 wild relatives, and group II contained 1 landrace and 6 cultivars. There were 117 cultivars and landcaces in the group III. (4) Being consistent with previous publication, the divergence time of the wild relatives was the longest, followed by local accessions, whereas cultivars were the shortest. Moreover, the divergence time of Fujian landraces and the cultivars from Philippines was same, indicating the evolution pathway of sweet potato from The Philippines to Fujian province of China is believable. In conclusion, SRAP is a useful method for deciphering the genetic diversity and origin of sweet potato germplasm.