Abstract: This paper introduced the study on insect resistance, disease resistance, weedicide resistance, stress tolerance, improving quality, improving development, increasing photosynthesis and efficiency of azotification in crop breeding, and expatiated methods and benefits of gene engineering in improving crop variety. The important crops acquired by gene engineering have included soybean, maize, cotton, rapeseed and tobacco. These crops have been planted in agricultural production and acquired enormous benefits of economy, society and environment. Analyzed the prospect of genetic engineering in crop breeding and hope to cultivate special crop variety. The problems of scarce resource, deteriorating environment and declining benefit have been solved, insured persistence and stabilization of agricultural development.