The invention relates to a plant growth regulator. The plant growth regulator comprises the following raw materials by weight percent: 25-40% of a compound microorganism bacterium agent, 20-40% of plant tea cypress extract, 25-35% of yeast waste liquid and 10-20% of compound amino acid solution. According to the plant growth regulator, plants can be effectively promoted to improve the resistance, phytotoxicity and fertilizer damage are eliminated, the generation of fruit-vegetable crop diseases such as root rot, damping off, gummy stem blight, downy mildew, epidemic disease, powdery mildew, stalk break, verticillium wilt, stem rhizoctonia rot, fruit rot, bacterial wilt, deficiency disease, virus disease and root-knot nematodes caused by fungus, bacteria and virus is inhibited, original quality and mouthfeel of crops are restored, and the problems of high residuals for nitrite and heavy metals such as plumbum, arsenic, cadmium and mercury are thoroughly solved.