A simple method for the determination of imidaclothiz residue in soil and citrus samples was established by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) under the multiple reaction monitoring (MRM) mode. Imidaclothiz was extracted from soil and citrus samples using a procedure known as the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method. Experiments on 3 fortification concentrations were carried out, and the limit of determination is 1.0×10-10 g. The recoveries ranging from 80.7% to 118.9% with high correlation coefficient (r>0.99) were obtained within the linear range (0.01-1.0mg/kg). Based on the above method, we also carried out field trials. Results showed that the degradation of imidaclothiz coincided with the fitted equations Ct=0.1028e-0.0266t, Ct=0.1778e-0.0311t in soil and Ct=1.3612e-0.0632t, Ct=0.7162e-0.0968t in citrus, respectively, with the average half-lives of 24.2 d in soil and 9.1 d in citrus, respectively. The results indicate that the developed method is fast, accurate, and easy to operate. It also demonstrates that the method can meet the requirements of determination of imidaclothiz in soil and citrus.