城市地铁建设规模逐年扩大，而地铁工程的造价水平逐年走低。对合价包干项目合理技术优化，逐渐成为施工企业利润主要增长点。结合工程实例，从明挖、暗挖工程两个方面分析合价项目技术优化的途径，通过介绍优化方案后创造的经济效益，指出适当优化技术方案，不仅可以为项目获取高利润，还能提高施工效率。

 The construction scale of the urban Metro works in China is becoming larger and larger. However, the construction cost of the urban Metro works is becoming lower and lower. Making rational technical optimization on Metro works based on lump sum contract has become one of the most important means for construction enterprises to make more profits. On basis of works cases, the author analyses the technical optimization means of the cutandcover Metro works and mining Metro works based on lump sum contract. The technical optimization has achieved good economic efficiency. The author concludes that appropriate technical optimizations can not only achieve better economic profit, but also can achieve better construction efficiency.