In this paper, transaction cost is introduced into the general firm-level export behavior model. By so doing, we build a theoretical model explaining how connection modes between leading agribusiness enterprises and rural households affect the firm-level agricultural products export. Analyzing the dataset of 561 national leading agribusinesses of the year 2003, we use Tobit model to estimate the firm-level export effect of the connection modes. The empirical result demonstrates that connections in the mode of stock-cooperation or cooperation contracts have a significant positive effect on the enterprises export and export ratio. In addition, the connection with more characteristics of factor contract has stronger effect on export than that with commodity contract characteristics.