OBJECTIVE： To investigate the correlation of 5-hydroxytryptamine 2A receptor （5-HT2AR） rs6313 gene polymorphism with pain occurrence and opioid requirements in patients with lung cancer. METHODS： Totally 332 patients with lung cancer were selected from the Affiliated Hospital of Xuzhou Medical University during Dec. 2017-Jun. 2018 as lung cancer group. They were divided into pain group （177 cases） and painless group （155 cases） according to whether pain occurred. Totally 116 healthy persons who underwent physical examination in same period were selected as control group. The genotype of rs6313 locus of 5-HT2AR gene was detected by PCR-RFLP. The distribution of genotype was compared by χ2-test. The correlation of genotype with pain occurrence and degree， opioids requirements were investigated by Binary Logistic regression analysis， χ2-test and Kruskal-Wallis test. RESULTS： CC， CT， TT genotypes were detected in rs6313 locus of 5-HT2AR gene. The frequency of above genotypes were 20.7％， 47.4％， 31.9％， 20.6％， 50.3％， 29.0％ as well as 16.4％， 50.8％， 32.8％， respectively in control group， painless group and pain group. Their frequencies and allele frequencies were in line with Hardy-Weinberg balance （P＞0.05）. There was no statistical significance in genotype and allele frequencies between lung cancer group and control group （P＞0.05）. TNM staging （Ⅲ-Ⅳ stage） was associated with pain in lung cancer patients [OR＝3.661， 95％CI （1.972，6.797）， P＜0.001]. Gender， age， height， body weight， pathological typing and rs6313 locus genotype had no correlation with pain （P＞0.05）. The genotype of this locus was not related to the degree of pain and the requirements for opioids in patients with lung cancer （P＞0.05）. CONCLUSIONS： The polymorphism of 5-HT2AR gene rs6313 locus is no related to pain occurrence and opioid requirements in patients with lung cancer. Its polymorphism may not be the main cause of individual pain differences in lung cancer patients.