In spacecraft applications, a step-up converter used to the battery discharge regulator (BDR) should provide a sufficient phase margin and wide bandwidth to satisfy highly demanded requirement of the bus voltage regulation. Thus, Weinberg converter, which has no right half plane zero, has been widely used. However, Weinberg converter requires lots of components, so that BDR cannot avoid the power density degradation. In additions, due to the leakage inductances the output current spike increases output voltage ripple largely. In order to overcome the abovementioned problems, a new boost-forward integrated converter is proposed. Comparing with Weinberg converter, the proposed converter has small magnetic size and eliminates one powering diode. At the same time, there is no the output current spike. In additions, it has a high phase margin and bandwidth. Therefore, the proposed converter is adaptable to increase the power density of spacecraft applications especially BDR. The improvement of proposed converter is verified by 500W/50V prototype model.