China is a big agricultural country，long-term use of fertilizer will not only cause waste of resources，but also lead to soil quality decline，crop yield reduction，pollution intensification and other problems，and even endanger human public health. Microalgae bio-fertilizer has become a potential new functional fertilizer because of its wide range of raw materials，rich nutrients and active substances. In this paper，the preparation forms and formulations of microalgae biofertilizer，as well as its role in soil-crop system and soil pollution remediation were reviewed. The results showed that the main type of algae fertilizer was liquid，and the effect of mixed type was better than that of single type. Microalgae could increase the nutrient content of soil through their own photosynthesis，nitrogen fixation and carbon fixation，and stimulate the germination and growth of crops and nutrient absorption through their own cell activity and metabolism of active substances，so as to improve the yield and quality of agricultural products. Most importantly，microalgae could increase soil enzyme activity and microbial activity，thereby improving soil microecology，repairing soil desertification and acidification，and reducing soil pollutant content. Finally，this research made a prospect on how to optimize the algae species and give full play to the role of microalgae in reducing carbon and fixing nitrogen in agriculture，in order to provide a useful reference for the agricultural application of microalgae biological fertilizer.