In Viet Nam, HFMD outbreak In 2012 has identified the cause of the illness was EV71 (accounting for 68.2 percent), Including EV71 - C4 species accounted for 58.44 percent. To select the appropriate strains for further research and vaccine production, 200 EV71-C4 positive speciments were selected for culture. Results show that 127 strains were successfully isolated with 100 strains were sequenced and compared with the previous nucleotide sequences. The similarity of the nucleotide sequences between before and after culture of isolation showed 96 percent. Of the 100 strains were sequenced , 35 isolates revealed sequence VP1 region of high similarity and differences from other strains as well as several strains have been used to study vaccines in the world. Among these strains, 7 strains satisfy the selection criteria for study as vaccine production, e.g: the most common pathogenic strains, posscess the highest sequence similarity (99.4 to 99.6 percent) with specific genetic characteristics of pathogenic strains in Vietnam and the ability to grow well on the cultured cells.