In order to expand ideas for improving the insufficient capacity of many crude oil import terminals in China, this study examined the capacity improvements of a crude oil import terminal consisting of a navigation subsystem and a terminal subsystem. As the navigation subsystem featured a one-way navigation channel, we focused on the scenario of adding berths for unloading and building a ship-passing anchorage(SPAC)as a buffer zone. The terminal capacity and the tanker average delay time under different scenarios were obtained through simulation with the software Arena. A case study of the Shihua Terminal of the Rizhao Port shows that the marginal increase in the capacity of the crude oil import terminal decreases with the mere increase of the unloading berths; that the percentage increase in the capacity, as a result of building a SPAC, increases with the added unloading berths; and that adding unloading berths and building an extra anchorage area concurrently reduce the average delay time of tankers at the port significantly.