With the acceleration of industrialization, modernization of agriculture and animal husbandry and urbanization, the pressure of water environment and water pollution are also increasingly prominent. However, agriculture, industry, service industry and the whole society have an increasing demand for water resources, and the contradiction of water resources shortage is also increasingly obvious. In this case, although some water pollution (WP) prevention measures have been put forward, there are still some risks in WP prevention. In this regard, this paper studied the risk factors and evaluation of WP prevention and control based on the fuzzy Bayesian network. It put forward the prevention and control risk factors such as the risk of pollution prevention and control laws and regulations, the risk of prevention and control management mechanism, and evaluated and studied the risk levels of WP prevention and control in the three urban areas of Z City. The results showed that the risk index of WP prevention and control in D, X and Q districts was 45.9, 51.5 and 49.3 respectively from the perspective of average value, and the risk level of the three urban areas was acceptable; from the perspective of fuzzy Bayesian network, the risk level of WP prevention and control in D, X and Q areas also belonged to the acceptable risk level.