Abstract: To study the residue degradation dynamics of iprodione in bayberry fruits, the residual trial of iprodione in bayberry were carried out by two ways from 2014 to 2015, one was spraying once and sampling repeatedly, another was spraying in different periods while sampling once in mature period. The results showed that the degradation of iprodione in‘Dongkui’and‘Linhaizaodamei’fruits were in conformity with the firstorder kinetic model, and the half-life period was 9.2 d and 13.86 d, respectively. The degradation velocity of iprodione in bayberry fruits was slow, but the residue concentration in bayberry fruit was significantly lower than the maximum residue limit (MRL) 5 mg/kg of apple and pear in China, Hong Kong and Japan. If sprayed one time with 1:1000 dilutions during young fruit period.