Based on the research data from the economics and management platform of Inner Mongolia Agricultural University, we analyze the changes in the input of agricultural production factors, such as farmland, labor and capital in Hohhot City. Based on the principle of econometrics, we select the agricultural production input-output data in Hohhot City during the period 1992-2010, and establish the econometric model using Cobb-Douglas production factor, to estimate the rate of contribution of agricultural input to the growth of agricultural output value, and study the quantitative relations between agricultural input and agricultural output value. The results show that in Hohhot City, the contribution of chemical fertilizer input to the growth of agricultural output value is the greatest; the contribution of mechanical power to agricultural output value is still not brought into full play; the contribution of remaining production inputs (including technical progress) accounts for 35.69%. In the future, Hohhot City should pay more attention to the technical input to develop agriculture.