Abstract: With development of rural society and economy，rural water consumption and waste water volume are increasing day by day.In order to effectively treat waste water and make it reach discharge standard stably，selection of functional strains from local domestic waste and waste water to strengthen local A/O waste water treatment system were studied.Two highly efficient COD removal bacteria and two nitrogen removal bacteria were screened from local samples and the bacteria were used in secondary A/O wastewater treatment system.Results showed that COD removal rate increased by 6.5% on average，total nitrogen removal rate increased by 11.6%，and amino nitrogen and nitro nitrogen removal rates increased by 33.0% and 26.8%.