Objective To explore the impact of residual symptoms on psychosocial function of patients with euthymic bipolar disorder. Methods A cross-sectional study was conducted. A total of 81 patients with euthymic bipolar disorder diagnosed by ICD-10， who were admitted to the outpatient clinic of the First Hospital of Hebei Medical University from November 2019 to December 2020， were enrolled in this study. The demographic survey was conducted. The residual mood symptoms were measured by Hamilton Depressive Scale 24 items （HAMD-24）， Hypomania Check List （HCL-32） and Hamilton Anxiety Scale （HAMA）. Hopkins Verbal Learning Test revised （HVLT-R）， Brief Visuospatial Memory Test revised （BVMT-R）， Trail Making Test A（TMT-A） and Digit span task （DST） were used to assess the residual cognitive symptoms. The Global Assessment Function （GAF） was used to evaluate the psychosocial function. The patients were divided into two groups according to the score of GAF： high social function group （GAF=9） with 27 cases and low social function group （GAF ＜ 9） with 54 cases. All the data were analyzed by SPSS 22.0. Results Compared with the GAF=9 group， the GAF ＜ 9 group had more female ［40.7% （22/54） vs 33.3% （9/27）］， lower level of education ［12.00（9.00，13.00） vs 16.00（12.00，16.00）］， more unemployed ［40.7% （22/54） vs 18.5%（5/27）］， higher dosage of antipsychotics ［（10.48±5.40） vs （7.99±5.65）］ mg， higher HAMD score ［6.00（3.75，10.00） vs 3.00 （0，6.00）］， lower BVMT-RT1 score ［4.00（1.00，8.00） vs 6.00（3.00，10.00）］， lower BVMT-RDR score ［7.50 （3.00，11.25） vs 11.00（8.00，12.00）］ and lower DST score ［14.00（12.00，16.00） vs 15.00（13.00，18.00）］. The differences in gender， education， marriage， profession （χ2 =9.00， P=0.03）， smoking history， drinking history， past history， the use of mood stabilizers， antidepressant， benzodiazepines， the score of HAMD， DST， BVMT-RT1， BVMT-RDR were statistical significant （P ＜ 0.05）. The overall function of patients with euthymic bipolar disorder was correlated with education level （r=-0.34，95%CI=-0.53- -0.12， P＜ 0.01）， HAMD （r=0.37，95%CI=0.16-0.56，P＜ 0.01）， BVMT-RT1 （r=-0.23，95%CI=-0.41- -0.02， P=0.04）， BVMTRDR （r=-0.24，95%CI=-0.45- -0.02，P=0.03）， DST （r=-0.23，95%CI=-0.42- -0.01，P=0.04） and the use of antipsychotics （r=0.23， 95%CI=0.02-0.44， P=0.04）. In patients with euthymic bipolar disorder， the residual depressive symptoms （χ2 =5.33， OR=1.58， 95%CI=1.07-2.33， P=0.02） and the use of antipsychotics （χ2 =4.77， OR=1.37， 95%CI=1.03-1.82， P=0.03）were the risk factors of psychosocial function impairment， and high level of education was a protective factor （χ2 =5.31， OR=0.34， 95%CI=0.14-0.85， P=0.02）. Conclusions The risk factors of psychosocial function impairment in patients with euthymic bipolar disorder include residual depressive symptoms and use of antipsychotics. The protective factor for maintaining psychosocial function in patients with euthymic bipolar disorder is high level of education.