The invention provides a specific complex herbicide for asparagus and its application. The high-efficient haloxyfop-P, fluazifop-butyl, fluroxypyr and 2-methyl-4-sodium chlophenoxycetate of the existed herbicide are compounded at a specific ratio to form active components of the complex herbicide; compared with single-dosage pesticide, the complex herbicide after combination has significant weeding effect to gramineous weeds and broad leaf grass; thus the drug effect is high, the preventive effect is good, and the drug dosage can be reduced, the pesticide residue and ecological environment pollution in the asparagus are reduced; moreover, the specific complex herbicide is also featured by rapid effect and effect persistence; more importantly, the specific complex herbicide is safe for the immature stem of the asparagus and free from drug harm; therefore, the specific complex herbicide can replace the traditional manual weeding method of the asparagus field, and the manual cost is largely reduced.