Abstract: In order to guarantee navigation safety,and to identify safety factors of passenger ships in inland rivers at nighttime,the factors that affect navigation safety are classified into 4 categories,which are human and ship,natural en-vironment,port,and management.An index system for risk evaluation of navigation for passenger ships at nighttime is established.Combining Analytic Hierarchy Process(AHP)and entropy weight theory,influences of subjective and objec-tive factors can be alleviated in weight distribution of each evaluation index.The unascertained theory is used to deal with randomness and uncertainty of evaluation indices in the model.Taking the Haihe River in Tianjin as a case study,an un-ascertained model is used to evaluate navigation risk of passenger ships at nighttime.The results show that weight ratios of 5 factors are larger than others,including crews,ship seaworthiness,intensity of background light,safety manage-ment of ships,and shipping companies.The risk level of navigation at nighttime in Haihe River is"normal"and its confi-dence is larger than 70%.