The invention relates to a plant growth regulator capable of increasing the yield and a preparation method of the plant growth regulator. The plant growth regulator capable of increasing the yield isprepared from, in parts by weight, 20-30 parts of indoleacetic acid, 3-6 parts of thiophanate methyl, 5-10 parts of water-soluble chitosan, 5-8 parts of cloxyfonac, 5-9 parts of ABT rooting powder, 1-2 parts of potassium dihydrogen phosphate, 1-3 parts of manganese sulfate, 2-5 parts of plant ash, 2-5 parts of gingko leaves and 1-5 parts of christina loosestrife herb. Through the plant growth regulator capable of increasing the yield, the growth requirements of plant can be met, the growth and development of the plants can be promoted, the yield of the plants can be increased, and no residuesis left in the plant bodies.