In modeling a pneumatic system with fluid-flow and thermal fields by bond graph method, two kinds of bonds, multi-port C and multi-port R elements have been used. Hence, the resulting bond graph model becomes complicated. To overcome this problem, one of the authors had proposed a new bond graph method by introducing a new definition about effort and flow. However, the simulation based on the bond graph model derived by the proposed method seems to be difficult since the denominators of effort and flow include variables such as density and temperature of air, and coefficient of TF-element is variable. Therefore, it seems to be difficult to use the proposed method in the simulation of a practical pneumatic system. Hence, in this study, another bond graph method for modeling a pneumatic system is proposed. In modeling of fluid flow fields, pseudo bond-graph is employed. In the proposed method, a kind of bond, 1 -port C element, 1 -port R element and TF-element with a constant coefficient are used for modeling of such a system. To confirm the validity of the proposed method, simulation for a simple pneumatic system is carried out. By comparing the simulated results with the experimental ones, the validity of the proposed bond graph method is clarified.