Objective To study the cognitive function and nervous system soft sign of first-degree relatives of patients with obsessive-compulsive disorder（ OCD）. Methods From June 2015 to June 2017， a total of 70 OCD patients in Jingzhou Mental Health Center were selected and divided into high incidence family group and sporadic family group. This research adopted Hamilton Anxiety Scale（ HAMA） for anxiety symptoms in first-degree relatives， Yale Brown Compulsion Scale（ Y-BOCS） for obsessive disorder， Wisconsin Card Sorting test（ WCST）， Trupp Color Words Test（ Stroop）， Continuous Operation Test（ CPT） for the cognitive function， and the soft sign subscale of Cambridge Neurology Examination（ CNI） for soft sign of nervous system. Results The total scores of Y-BOCS and HAMA in high incidence families were significantly higher than those in sporadic families（ t=4.85，2.61； P＜0.05）. The scores of Stroop test， WCST scale， CPT scale， and memory scale were all lower than those of the sporadic families， and the differences were statistically significant（ P＜ 0.05）. The total score of NSS and its motor coordination subscale and sporadic pedigree were all higher in the high incidence family group than the sporadic family group（ t=2.15，3.03，3.14；P ＜ 0.05）. Conclusions The first-degree relatives in high incidence families had more anxiety and obsessive-compulsive disorder symptoms than those in sporadic families. They were also more likely to develop nervous system soft sign and cognitive impairment of attention and memory.