The invention discloses a fertilizing, sowing and weeding device of a tillage machine. The fertilizing, sowing and weeding device comprises a rotary cultivator, a stand, a fertilizer applicator, a seeder, a transmission gear set, a transmission shaft, a bearing sleeve, a power wheel, a connecting rod, a movable rod, a spring, a fixed piece, a medicine liquid tank, a water pump, a water pipe, a spray head and a ridge-former, wherein the stand is fixedly connected on the rotary cultivator by screws; a metal ring is welded at one end of the connecting rod and sleeves on the bearing sleeve, and the powder wheel is arranged at the other end of the connecting rod; the power wheel is connected with the transmission shaft by a chain; the fixed piece is welded in the middle of the stand, and a circular hole is formed in the middle of the fixed piece; the lower end of the movable rod is connected with the connecting rod by a pin shaft, and the upper end of the movable rod passes through the circular hole of the fixed piece; the spring sleeves on the movable rod, and the upper end and lower end of the spring respectively lean against the fixed piece and the connecting rod. The fertilizing, sowing and weeding device has the advantages of being simple in structure, high in practicality, and the like.