Abstract: Nested PCR method was used to amplify the Plasmodium vivax merozoite surface protein 1 （PvMSP-1） gene fragment containing the ICB5 and ICB6 region from Plasmodium vivax in Liaoning Province． The PCR products were digested by PvuⅡrestriction endonuclease and the digested fragments were observed by 1.5% agarose gel electrophoresis，and all followed by sequencing analysis and comparion． In 11 field isolates of P. vivax, two kinds of DNA fragments with 470 and 400 bp were produced respectively. After PvulI digestion，two Sal-1 type fragments （120 and 350 bp） were obtained from 5 samples of 470 bp． Single band of 400 bp appeared in 1 samples as Belem type． Two bands of 120 and 280 bp appeared from another 1 sample as recombination type III，and other 4 bands with 120 and 240 bp as Korean isolate． The principal types of PvMSP-1 alleles exist in malaria endemic areas in Liaoning Province with no mixed infection of two different type alleles.

Key words: Plasmodium vivax, Merozoite surface protein 1, Allele, Sequence analysis