Objective: To understand the current situation of suicidal ideation in college students of Tianjin, and to provide reference for suicide prevention, early warning and emergency intervention. Methods: A total of 31 596 freshmen from one university in Tianjin were selected to participate in the mental health survey during 2013 to 2020. Results: A total of 1 349 freshmen reported suicidal ideation. The incidence of suicidal ideation varied from 2.60% to 6.18% across the years (the overall average annual incidence of suicidal ideation was 4.27%). Significant differences were observed in the incidence of suicidal ideation among freshmen of different origin (4.11% in urban areas, 4.74% in rural areas; χ 2=6.01, P <0.01), whether the only children in the family (4.10% in only children, 4.60% in non only children; χ 2=4.38, P <0.01). During the past five years, the in depth interview showed that the proportion of those with suicidal attempt ranged from 17.09%-33.73% (the total annual average proportion of those with suicidal attempt was 24.84%). Results from electroencephalonquadrantography varied significantly between college students with and without suicidal ideation and those with and without suicidal attempt. Conclusion It is necessary to strengthen the screening of college students for suicidal ideation and to identify the risk of students with suicide attempt, so as to provide a better reference for the prevention and intervention of psychological crisis.