Objective To investigate the correlation between OPRM1 A118G gene polymorphism and Eysenck personality type and pain sensitivity. Methods The surgical patients who were transferred from Department of Emergency Medicine to Department of General Surgery of Luzhou People’s Hospital between January 2018 and December 2020 were selected. Before surgery, Eysenck Personality Questionnai (EPQ) was used to investigate the patient’s personality type, and the pain threshold and pain tolerance threshold were determined by electric stimulation instrument. The OPRM1 A118G genotype of peripheral venous blood was detected by polymerase chain reaction-restriction fragment length polymorphism analysis technique. Patients were divided into wild homozygous (A/A) group, mutant heterozygous (A/G) group and mutant homozygous (G/G) group according to the typing results. The general condition, pain sensitivity, EPQ score, difference of Eysenck personality type and correlation between Eysenck personality type and pain sensitivity were analyzed. Results A total of 356 patients were enrolled, including 174 in A/A group, 136 in A/G group and 46 in G/G group. The mutation rate of OPRM1 A118G gene was 32.00%. There were statistically significant differences in pain sensitivity (pain threshold, pain tolerance threshold) and scores of introverted and extraverted, neurotic and dissemble personality types among three groups (P<0.05). There were significant differences in introverted and extraverted and psychotic personality types among the three groups (P<0.05). There were significant differences in pain threshold and pain tolerance threshold among different introverted, extraverted and psychotropic personality types (P<0.05). Conclusion Both OPRM1 A118G gene polymorphism and Eysenck personality type have influence on pain sensitivity, and there is a correlation between them.