Oil spill is an irreversible environmental pollution accident which will damage the water quality and destroy ecosystem. The risk of oil spill should not be overlooked. Minjiang River downstream has a number of water intakes and wetland protected areas. During Minjiang channel construction period and operation period there are risks of oil spills, which may have an impact on the environmentally sensitive targets. According to the conditions of the project area and the requirements of the project construction, this paper uses the two-dimensional unsteady model as a platform to establish the hydrodynamic model of Minjiang River downstream, then analysize Model reliability based on measured data. Based on the accurate hydrodynamic model, establish the oil spill accident prediction model guided by “oil particle” tracking technology to predict the risk of oil spill accident under the most unfavorable conditions of the construction and operation period of the Minjiang River, which provide support for the MInjiang emergency response, oil spill damage assessment and safety management of water intake. Presenting a set of methods and ideas for risk prediction of oil spill accidents and providing a reference for the active prevention of oil spill accidents.