The opportunism and asymmetric of information, gives birth to hold up, low-investment and moral hazard with hidden information between owner and contractor in the contract variation.

• 摘要承发包双方在合同变更中的机会主义和信息的非对称性，产生了“敲竹杠”和投资过小现象以及隐藏信息的道德风险问题。