The present invention discloses a plant growth regulator composition having synergistic effect. The effective ingredients of the composition comprise active components A and B, wherein the active component A is thidiazuron, and the active component B is brassinolide or a derivative thereof. Also provided are a preparation method and use of the composition. Experimental results indicate that the composition of the present invention is effective in regulating the growth, increasing the disease and stress resistance, promoting the health and increasing the yield of crops.
