The invention provides fertilizer having no pesticide residue and excellent resistance to diseases. Through control of a fermentation temperature, an oxygen-containing environment and fermentation time of Trichoderma microorganisms, Bacillus subtillis and organic matters without chemical pesticide and antibiotic residual, organic fermentation products are controlled, then the Trichoderma fermentation product and polyglutamic acid are mixed and undergo a reaction, the Bacillus subtillis fermentation product and chitosan oligosaccharide are mixed and undergo a reaction, and the reaction products and chemical fertilizer are mixed and undergo a reaction to produce a complex, wherein nutrients are transferred into the complex. Through control of N, P2O5 and K2O in the fertilizer, normal growth of a tea tree is kept and a yield and nutrient content are improved. Through reasonable proportioning of N, P and K contents and conversion of N, P and K into complexes, amounts of elements needed by a tea tree in different growth periods are guaranteed and tea tree resistance to diseases is improved. The fertilizer reduces tea white scab, tea gall, anthracnose and root rot morbidity and effectively prevents negative factors such as tea pesticide residues, harmful microbes and toxins.