Objective To explore whether tumor necrosis factor receptor-associated protein 1 (TRAP1)gene copy number variation was associated with susceptibility and clinical characteristics of systemic lupus erythematosus (SLE).Methods The study enrolled 304 SLE patients and 391 healthy controls.They were used to investigate the association between TRAP1 gene copy number variation and SLE susceptibility.Then,304 SLE patients were divided into copy number=2 group and copy number＞2 group to study the association between TRAP1 gene copy number variation and disease activity or clinical characteristics of SLE.AccuCopyTM Kit was used to detect the TRAP1 gene copy number.Data analyses were performed by SPSS 10.01 software.The suitable method was selected among t test,rank sum test and x2 test for analysis based on the data type and distribution,univariate and multivariate logistic regression analysis were performed to investigate the associ-ation between TRAP1 gene copy number variation and susceptibility and clinical characteristics of SLE.Results The copy number variation of TRAP1 gene showed an association with the susceptibility to SLE crude OR=5.257,95％CI (1.108,24.937),P=0.037;the adjusted OR=5.578,95％CI (1.172,26.556),P=0.031].There was no association between TRAP1 gene copy number variation and SLE disease activity index (SLEDAI) score (Z=-0.117,P=0.907).The copy number variation of TRAP1 gene had a marginal association with skin lesions in SLE [OR=0.130,95％CI (0.016,1.069),P=0.058],but it disappeared after adjusting for potential confounders [OR=0.288,95％CI (0.029,2.831),P=0.286,PBH=0.808].There was no correlation between TRAP1 gene copy number variation and arthritis,alopecia,oral ulcers,fever,hematologic disorder,lupus nephritis as well as photosensitivity in SLE [x2=0.751,OR=1.234,95％CI (0.767,1.988),P=0.386].No multiplicative interaction was found between TRAP1 gene copy number variation and age or body mass index (BMI) [age:x2=0.751,OR=1.234,95％CI (0.767,1.988),P=0.386;BMI:x2=0.282,OR=1.172,95％CI(0.652,2.109),P=0.596].Conclusions The copy number variation of TRAP1 gene may be associated with susceptibility to SLE.Increased TRAP1 gene copy number may be a risk factor for SLE.