The main conclusions are as follows:(1) When study the data of long-term which is collected off Sydney in Tasman Sea, the Annual N-Largest method is the best one, secondly, the Peak-Over-Threshold method, and thirdly, the Annual Maximum method.

• 对澳大利亚悉尼观测站资料研究表明，利用长期资料设计波高时，采样方法选用年N大波法最优，其次是波高阈值法，建议不要使用年最大值法。