The invention relates to a biological regulator with a function of increasing fruit setting percentages of fruit vegetables and a method for preparing the biological regulator. The biological regulator comprises, by weight, 6-10 parts of 2, 4-dichlorphenoxyacetic acid, 6-8 parts of diethylaminoethyl hexanoate DA-6, 7-10 parts of forchlorfenuron, 3-5 parts of sodium nitrophenolate, 0.5-1 part of falling preventive elements, 4-5 parts of gibberellin, 8-10 parts of benzylaminopurine, 3-5 parts of dispersing agent ethylene-vinyl acetate copolymers, 2-3 parts of emulsifiers OP-10, 4-6 parts of antifreezing agents ethylene glycol and 100-150 parts of absolute ethyl alcohol. The biological regulator and the method have the advantages that the biological regulator is wide in acting surface and canbe applied to multiple fields; photosynthesis, respiration and substance absorption and translocation of plants can be regulated and controlled, physiological procedures for signal transduction, stoma opening and closing, osmotic adjustment, transpiration and the like can be adjusted, and accordingly growth and development of the plants can be controlled; the biological regulator is low in usage,high in speed and benefit and little in residual toxicity, and only needs to be sprayed once for most fruit vegetables in each season according to set time; the biological regulator rarely can be affected by environments, the fruit setting percentages of the fruit vegetables can be increased by the biological regulator, use modes for the biological regulator are easy and convenient to operate, and the time and labor can be saved.