The Bayes method sampling plan of water saving irrigation products was established by using the prior data and experiment. The Bayes sampling plan results of plastic pipes, microirrigation emitters and rotating sprinkler were collected and showed the sample decrease ratio E mainly had a relationship with prior product qualified ratio variance S2R and average Ra. In normal lot it was less than 1200, if S2R=0.002 and Ra=0.95, sample decrease ratio of plastic pipes and micro-irrigation emitters was higher than 62%, also sample decrease ratio of rotating sprinkler was higher than 85%. Compared with normal sampling plan, the Bayes sampling plan could reduce the sampling number more than 20% in the condition of same inspection effect; therefore the Bayes sampling plan reached the purpose of reducing the sampling number, lowering the inspection cost and increasing the inspection benefit.