The invention relates to the technical field of pesticides, more specifically, the invention relates to a pesticide composition and a preparation method thereof. In parts by weight, at least the following components are included: 90-100 parts of mineral oil, 1-8 parts of multi-carbon chain organic matter, 0.1-1 part of dispersant, and 0.1-1 part of auxiliary agent. The present invention adopts mineral oil, multi-carbon chain organic matter, dispersant, and auxiliary agent to jointly prepare the pesticide composition, and the mineral oil, multi-carbon chain organic matter, dispersant, and auxiliary agent have a good synergistic effect, and the prepared agricultural chemical composition It can prevent and control a variety of pests, and has high activity on spider mites, panonychia, aphids, whitefly, whitefly, short beard mite, rust mite, etc. on vegetables, fruit trees, cotton, rice and other crops. Excellent, long-term control effect, and greatly reduce the dosage. In addition, the pesticide composition of the present invention achieves the effect of controlling pests through physical action, basically has no residue on crops, is harmless to human body and environment, and pests will not develop drug resistance.