Objective To analyze the difference of brain function stability among patients with bipolar disorder （BD） in remission （EP）， patients with BD depression （DP） and healthy controls. Methods A total of 56 patients with BD treated in Beijing Anding Hospital Affiliated to Capital Medical University from February 2009 to June 2016 were selected as the study group， and were divided into EP group （n=30） and DP group （n=26） according to their emotional state. Another 71 healthy controls matched with patients in the study group were recruited as the healthy control group. The degree of depression among EP group， DP group and healthy control group were compared by Hamilton Depression Scale （HAMD-17）. Resting state functional magnetic resonance imaging （fMRI） data of all subjects were collected. DPABI software was used to preprocess the data and calculate the functional stability index， to compare the differences of the three groups of functional stability. Repeated verification was carried out using different window width， step size and window type. Pearson correlation was used to analyze the correlation between the functional stability of the right posterior cerebellar lobe and the total score of HAMD-17. Results The total score of HAMD-17 in the EP group， the DP group， and the healthy control group was ［2.00 （0，4.00） points vs 14.00 （10.75，19.50） points vs 0 （0，1.00） points］， and the difference was statistically significant （P＜ 0.01）. The functional stability of the right posterior cerebellar lobe of the three groups of subjects with different window width / step size / window type was compared， and the difference was statistically significant （P ＜ 0.05）. The functional stability of the right posterior cerebellar lobe in EP group was significantly lower than that in DP group and healthy control group （P ＜ 0.05）. There was no statistical significance in the difference of functional stability between DP group and healthy control group （P ＞ 0.05）. There was no correlation between the functional stability of the right posterior cerebellar lobe and the total score of HAMD-17 in the study group， EP group and DP group （P＞ 0.05）. Conclusions EP and DP patients show different brain function activity patterns， only EP patients show decreased functional stability of the right posterior cerebellar lobe.