AIM: To identify circumsporozoite protein (CSP) genes of Plasmodium vivax in Hubei endemic areas and explore the biological features of CSP polymorphism. METHODS: Circumsporozoite protein (CSP) gene of P. vivax in Hubei was firstly sequenced by using routine cloning and Sanger Chain Terminal method. RESULTS: The N- and C- terminus sequences flanking the central tandem repeat, including post-repeat variable region of CSP gene of HB2 isolate were identical to those of North Korean (NK) isolate and Southern China isolates (CH2-7) , while the central tandem repeat region existed extensive poly-morphism. Compared with the other CSP gene sequences published so far, the repeat form GNGAGGQP/AA and the post-repeat variable region had obvious geographical characteristics. Incidentally, one CSP gene PCR product of HB2 isolate produced two clones containing 0.75 kb and 1.1 kb DNA fragment, respectively. Their nucleotide sequences were almost the same except for three silent changes and one nonsilent change and the difference in the repeat number as well. CONCLUSION: The variation of CSP gene sequence, especially in the repeat and the post-repeat variable region, possibly involve the changes of latent period of P. vivax.