Abstract: Maize palnts were treated with PC compund plant growth-regulator at 0.3% comcentration during 10~12 leaves show that the growth-regulator can significanty decrease the plant height，ear height and increase the resistance to loding of maize.In the experiments of Yedan 13, Zhengdan 13, Yuyu 27 and Anyu 13, the plant height decrease by 24.2~50.2cm and the ear height decrease by 14.8~27.3cm compared with controls,and had a certain effect on its 100-grain weight，grain weight per ear and yield.In addition, the results of electrophoretic analysis of peroxidase isozyme and souluble protein showed that it could give rise to the change of maize on physiology and biochemistry level after PC plant growth-regulator treatment.