[摘　要]　通过分析尼日利亚阿卡铁路项目实际发生的两起合同验工条款索赔和两个优化设计变更的成功案例，总结合同索赔和设计变更的过程和取得的成果，分析总价合同和单价合同采用不同的处理方式，阐述合同索赔和设计变更时与咨询工程师或业主谈判的技巧，最后提出索赔和变更取得成功的重要条件，即紧抓合同，实现互利共赢。

[关键词]　国际工程；合同索赔；变更优化

Abstract: Based on the successful cases－two claims for the contract clauses of the measurement of work executed and two design variations optimization actually occurred in the Nigerian Railway Modernization Project, this paper summarizes the process and accomplishments of contract claims and design variations, analyzes the different treatments adopted for both lump-sum contract and unit price contract; states the negotiation skills for the project's employer or the consultant regarding to the contract claims and design variations. At last, the important conditions of the success for the claims and variations are put forward -basing on the contract tight to occupy the commanding point of the theory, following the strategy of mutual benefit and win-win results to create better benefit for the project.

Key words: international project; claim; design variation