Disclosed is a plant growth regulator composition with synergistic action, the effective ingredients thereof containing A and B, wherein active component A is thidiazuron, and active component B is brassinolide or a derivative thereof. Also provided is a method for preparing the composition and a use thereof. Experimental results showed that the composition of the present invention can regulate plant growth well, improve disease resistance and stress resistance, and promote healthy crops, so as to increase the crop yield.
