Abstract: To study the effect of droplet sizes on deposition and pesticide efficiency, this trial was performed to spray imidacloprid against aphids by choosing different nozzle types. The VMD of the three chosen nozzles from Lechler, i.e. LU120-02, AD120-02 and IDK120-02, were about 100 μm difference. The results demonstrated that: the deposits of IDK nozzle were higher significantly than that of LU and AD, whose deposits had no significant difference. The deposits on different zones of wheat canopy followed: down>middle>upper; LU nozzle achieved significantly better coverage rate than AD and IDK, the increased droplet size meant the lower coverage rate; LU nozzle had the largest ground loss and it was higher significantly than the other two nozzles; the three nozzles all gave excellent field efficiency against wheat aphids; AD nozzle was considered as the optimum candidate in terms of deposits, coverage rate and ground loss.