The buffered crossbar switch is a combination of crossbar-based switch architecture and combined input and output queueing scheme. It is promising to achieve good performance without complex implementation. In this paper we apply network calculus technique to study the delay performance of the buffered crossbar switch. We setup a service curve-based model for the path through which a flow traverses the buffered crossbar switch. Based on this model, we develop a technique that can determine the end-to-end service curve guaranteed to a flow and calculate the delay upper bound of this flow. Then we analyze the determining factors of this delay bound performance.