Agricultural credit is an important driving force for the economic development of pastoral areas, and the lending behavior is also very common among the herdsmen. Some herdsmen even repay the loans by means of “borrowing the new and returning the old”. Therefore, it is of great significance to explore the heterogeneous impact of agricultural credit on the income increase of the herdsmen. Using the survey data of pastoral farmers covering the four cities of Inner Mongolia in 2020, the two stage of least squares (2 SLS) was used to test the heterogeneous effect of agricultural credit on animal husbandry. The results show that the promotion effect of agricultural credit on the net income of pastoral households is relatively significant, mainly acting on livestock income and non-livestock income. There is obvious heterogeneity in the income effect of agricultural credit in pastoral households with different micro characteristics. It is better income effect of pastoral credit with higher income level, higher income effect of pastoral credit with rich human capital, and higher income effect of credit in pastoral households with short feeding time is more effective. In the results of the mediation effect analysis, agricultural credit can affect the livestock size of pastoral households and thus affect their income. In view of the above results, suggestions are put forward for further improving the financial literacy of pastoral families in the future, vigorously playing the role of inclusive finance and commercial credit, and increasing the credit support of pastoral families.