The contention-free protocols can provide strict quality of service and have been receiving growing attention. The IEEE point coordination function (PCF) protocol is a very basic and important contention-free protocol. However, its existing performance analysis method is tedious and complicated. This paper proposes applying the classic M/G/1 vacation model to analyze the delay performance of the PCF in a straightforward manner, thereby avoiding reconstructing a new analysis model as done in previous research. Compared with related work, our method is simpler and more scalable and our results are more general. Simulations show that our analytical results are very accurate for both homogeneous and heterogeneous traffic.