It is found that risk allocation has been regarded as a static and one-off activity through reviewing a large amount of literature which is concentrating on the level of technology. Therefore, the institutional attribute of risk allocation is weakened or even neglected. In this study, risk allocation in construction project is rethought from the perspective of incomplete contract, which is divided into two associated processes, i.e. the first risk allocation in the contract and risk reallocation during the performance of the contract. The findings indicate that the former is conceived as uncompleted naturally and can regulate the latter, while the latter has the attribute of governance and can complete or adjust the former. The establishment of the risk allocation framework is favorable to exert its inspiriting function in the contract and its governing function during the performance of the contract so that the efficiency and effect of risk allocation in construction project can be improved.