Abstract: Ordered Binary Decision Diagram (OBDD) is commonly used in network reliability calculation. When evaluating the network reliability based on OBDD, computation time mainly depends on the size of the operating OBDD, which mostly relies on the variable ordering of OBDD. An algorithm is called BF-OBDD which is considered as the Boolean Function-OBDD, and it is the optimization algorithm for computing the reliability of the network. This paper shows that the reliability of network can be improved considerably by using of the proposed BF-OBDD algorithm. The experimental results demonstrate that the improved algorithm has less OBDD node numbers which cost less time when calculating the network reliability.