OBJECTIVE To study the effect of arginine on biofilm formation of dental plaque and screen the target bacteria mechanism.MATERIALS AND Methods The effect of arginine on the formation of polymicrobial biofilm was evaluated in high-throughput active attachment biofilm model and the result was determined by CFU count.Then,the effect of arginine on growth curve and biofilm formation of Streptococcus mutans,Streptococcus sobrius,Streptococcus sanguinis and Streptococcus gordonii were done respectively.