The invention discloses a preparation method of an oxazoline insecticide. The method comprises the steps that a first compound shown in description is used as a starting raw material; through oximation and amide condensation, a second compound shown in the description is obtained; further, through NXS substitution, elimination and cyclization, the oxazoline insecticide is obtained. The method hasthe advantages that the intermediate purification difficulty is lowered; meanwhile, the product purification difficulty is also lowered, so that the product quality and yield are improved; the productcompetitiveness is finally improved.