The content of imidacloprid in pesticide is usually measured by high-performance liquid chromatography, which is precise but time-consuming. In the present work the content of imidacloprid in pesticide was measured by infrared spectroscopy with pressing potassium bromide troche (KBr). A comparison of infrared spectra between analytic imidacloprid and commercial pesticide showed that the absorption peak of imidacloprid at 939.2 cm(-1) is independent and can be used as the characteristic absorption peak for quantitative determination. The area from 947 to 925.8 cm(-1) for the infrared spectra of imidacloprid and its content meet the linear equation: Area = l.3665 x 10(-1) + 2.37 x 10(-2) x c, r = 0.99953. Finally, the authors could draw a conclusion that the method of NIR, instead of routine lab analysis, is feasible for the determination of imidacloprid in pesticide.