Abstract: The cost reduction and efficiency promotion of dairy cow breeding is the key to achieve the goal of revitalizing dairy industry in China. In this study, the differences in the cost and benefit of dairy cow farming of different scales during the period 2010-2018 were compared and analyzed, and the fundamental factors affecting dairy cow farming benefit of different scales were explored by multiple regression method. The results showed that the feed cost, labor cost and fixed asset depreciation of dairy cattle with different scales showed an increasing trend on the whole, the rate of feed cost was the largest, and the economic benefits of large-scale dairy cattle breeding are not outstanding. Each cost item had a significant impact on the net profit of different scale dairy farming. However, the key influencing factor for the profit of medium-scale and large-scale was the depreciation of fixed assets, while the labor cost was the key factor for small scale dairy farming. From the perspective of influence degree, each factor had the most prominent influence on the profit of medium-scale farming, and the least influence on large-scale farming. Based on this, suggestions were proposed, induding reasonable adjustment of feed formula to reduce feed cost of dairy cows; actively guiding the appropriate scale and striving to develop family ranch; different measures should be taken to reduce costs and increase efficiency according to different scale of dairy farming, so as to promote the competitiveness of dairy cattle breeding in China.