The invention relates to the field of compound fertilizers for crops and in particular relates to a long-acting slow-released compound fertilizer for improving the quality of sesame. The compound fertilizer is prepared from the following raw materials by weight parts: 28-30 parts of urea, 10-12 parts of calcium superphosphate, 25-28 parts of potassium sulfate, 8-10 parts of ground cereals, 30-35 parts of organic compost, 2-3 parts of shrimp shell meal, 10-20 parts of ammonium nitrate, 1-3 parts of copper sulfate, 2-3 parts of zinc sulfate, 1-2 parts of lignosulfonate, 0.1-0.2 part of nanocarbon, 0.01-0.02 part of sodium benzoate, 10-13 parts of an organic silicon emulsion, 5-6 parts of dry jackfruit shells, 0.1-0.2 part of titanyl sulfate, 10-12 parts of plant ash, 5-7 parts of dry thinleaf adina fruit rhizomes, 3-5 parts of bauxite, 0.01-0.02 part of calcium propionate and 3-5 parts of aids. According to the slow-released compound fertilizer, an adsorbent is prepared from the raw materials such as the dry jackfruit shells and the dry thinleaf adina fruit rhizomes, organic matter fermenting liquid with rich active ingredients and the raw materials such as the aids are mixed with the adsorbent, and the effects of controlling the fertility and improving the fertilizer efficiency are achieved by virtue of a slow-released coating agent, so that the utilization rate of nutrients in the sesame is high, the nutrients are quickly accumulated, the product quality is improved, and the planting benefit is high.