Abstract: For solving the bad wetting of the pesticide solution and the suitable concentration of the pesticide adjuvant for spraying the DST(dynamic surface tension) of several adjuvants (LAS,OP-10 and FT-248) and the dynamic contact angles(DCA) of little drop on paraffin and maize were determined.The effect of DST and DCA on wettability of spraying droplet was discussed.The results showed that the less DST,the less DCA, the better wetting effect,and the faster decreasing of DST, the faster spreading of the solution.DST as a parameter for studying wetting progress was more authentic than equilibrium surface tension(EST).