Proper Occasion for China's Coastal Port Construction

China's coastal ports have been facing great pressure since 2000, and higher actual accomplished throughput than port's handling capacity has come forth as a common phenomenon, especially severe in container ports. This paper puts forward the conception of port throughput adaptability, suggests the way to revise current computation for port capacity of throughput concerning main factors affecting the seaport's development, and at last, builds a port construction model which can confirm the opportunity and scale of China's coastal port construction properly. It could be believable that the method brought forward here is of strong applicable and practical, and could be the basis for the present seaport in confirming how to enlarge its production scale and when to build new berth.