Objective To explore the influencing factors of suicidal ideation in patients with bipolar disorder. Methods A total of 405 consecutive outpatients diagnosed with bipolar disorder from February 2013 to June 2014 in 7 hospitals of 6 cities in China were followed up. The general demographic and medical history of the patients were collected. The manic / hypomania and depressive symptoms were assessed by mood disorder questionnaire （MDQ） and 16-item Quick Inventory of Depressive Symptomatology Self-Report （QIDS-SR16） respectively. Suicidal ideation was assessed according to item 12 of QIDS-SR16. The general demographic data and clinical characteristics of patients with and without suicidal ideation were compared. Logistic regression analysis was used to explore the clinical characteristics of suicidal ideation. Results Overall， 16.8% of patients with bipolar disorder had suicidal ideation. Patients with suicidal ideation had a lower proportion of bipolar type I diagnosis （χ2 =7.42，P=0.007）， a higher total score of QIDS-SR16 （t=-16.4，P ＜ 0.001）， a higher proportion of moderate or more severe depression （χ2 =127.94， P ＜ 0.001）， and a high proportion of history of suicide attempts in the past 12 months （P=0.043）. In the overall patients， QIDS-SR16 scores were significantly associated with suicidal ideation （OR=1.43， 95%CI：1.32-1.56， P ＜ 0.001）. In subgroup of patients with bipolar I disorder， QIDS-SR16 scores were significantly associated with high suicidal ideation （OR=1.56， 95%CI： 1.39-1.75，P ＜ 0.001）. In patients with bipolar Ⅱ disorder， the onset of age at pre-30-year-old （OR=3.97， 95%CI： 1.13-14.02， P ＜ 0.001） and QIDS-SR16 scores （OR=1.29， 95%CI：1.13-1.46， P ＜ 0.001） were significantly associated with high suicidal ideation. Conclusions There is a significant positive correlation between severe depressive symptoms and suicidal ideation in patients with bipolar disorder.