Abstract: With the rapid growth of market-oriented economy, more and more Chinese corporations start to exploit foreign market. However, due to the long duration of project construction and the influence of many uncertain factors, such as local policies, natural disasters, price inflation, project costs will vary, it is certain that contractors will make a claim based on the contract items to protect their own right. The incidents occurred over the course of executing civil and metallic contracts were discussed, and the claim reasons, claim calculations and claim amount were introduced.