Microbial fertilizer plays an important role in promoting fertilizer reduction, efficient utilization of nutrient resources and green development of agriculture, due to its characteristics in increasing nutrient transformation, enhancing crop resistance, improving soil structure, and reducing environmental pollution. However, previous studies mostly focus on cash crops, while grain crops, especially dry farmland crops, are still lack of research. The efficacy of microbial fertilizer in all crops is not still clear. At the same time, the misunderstanding of cognition and usage caused by various types, functions and effects of microbial fertilizers hinders its wider application. Exploring the mechanism of microbial fertilizer's impact on the growth and development of food crops is helpful for promoting the improvement of agricultural production quality and efficiency, and also has important scientific significance for promoting the utilization and protection of black soil resources. Therefore, by sorting out the classification and efficacy of microbial fertilizer, this paper clarifies the mechanism of microbial fertilizers affecting the growth and development of grain crops, summarizes the effects and constraints of microbial fertilizer applied in dryland crops of black soil, and puts forward the existing problems and research prospects. The paper may provide scientific basis for the large-scale promotion and application of microbial fertilizer in dry farmland crops of black soil.