The invention discloses a cooling device for compound fertilizer. The cooling device comprises a seat box, wherein seat box supporting columns are fixedly connected to the two sides of the bottom of an inner cavity of the seat box, cooling mechanisms are fixedly connected to the outer surfaces of the seat box supporting columns, access hole grooves are formed in the positions, between the seat box supporting columns, of the two sides of the outer surface of the seat box, a conveying pipeline is fixedly connected to the middle position of the top of the seat box, the bottom of the conveying pipeline penetrates through the seat box and extends to the top of the inner cavity of the seat box, and cooling fans are movably connected to the positions, located on the front face and the back face of the conveying pipeline, of the top of the seat box. The invention relates to the technical field of fertilizer. Effective airflow agitation is carried out on the inside through the cooling fans, intermittent blanking is carried out while airflow cooling is carried out, the number of one-time cooling is reduced, meanwhile, fertilizer conveying is carried out through vibration generated by impact, the fertilizer is thrown up and falls down repeatedly, particles are loosened conveniently, the contact surface area of the particles and air is increased, the contact time of the particles and the air is prolonged, and the heat dissipation uniformity and the heat dissipation quality are improved.