Abstract: An endogenous credit network model is constructed,which introduces firm-bank and interfirm markets simultaneously,based on the bank loan links between the bank and firm agents and the trade credit links among firm agents. We set double constraints for firms' production. To further describe the behavior of the related agents,we introduce investments,dividend payments and deposit fluctuation into the model. Moreover,we also allow multi-period debt structures and relax some research assumptions made by related scholars. The simulation results show the upper-tail of firm size distribution can be well fitted with a power-law and the bank in-degrees of the firm-bank credit network fall into a two-power-law distribution.