Abstract: Objective To understand the genetic diversity and characteristics of clusters of HIV strains among MSMs in Tianjin. Methods Pol gene fragments were obtained from 100 newly discovered and transformed HIV-positive HIV-infected antiretro viral therapy (ART) -naïve MSM who visited a retrospective cohort study of MSMs from June 2013 to June 2017 in Tianjin, by viral plasma RNA extraction and amplification. Genetic, drug-resistance and phylogenetic analyses were used to evaluate the characteristics of HIV molecular clusters combined with patient demographic and behavioral characteristics within the context of the entire cohort. Results 60.0% (60/100), 28.0% (28/100), 6.0% (6/100), 4.0% (4100) and 2.0% (2/100) of the individuals were infected under HIV subtypes CRF01_AE, CRF07_BC, B, CRF55_01B and URFs. 7. 0% (7/100) of infectors had transmitted drug-resistance mutations. The TDR prevalence rates of different subtypes were 3.0% (3/100) of subtype B, 2.0% (2/100) of CRF01_AE, 1.0% (1/100) of CRF07_BC and 1.0% (1/100) of CRF55_01B. TDRs was predominantly towards NNRTIs 4.0% (4/100). In contrast, TDR to NRTIs and PIs were 2.0% (2/100) and 1.0% (1/100) respectively. We identified 13 transmission clusters including 31 infectors. There were statistically significant differences in subtype, registration and history of sexually transmitted diseases between clustered and non-clustered infected people (P<0.050). Conclusions Results from this study suggested that the prevalence trends of HIV-1 CRFs, URFs and TDR strains among MSM were not optimistic. More attentions should be paid for prevention and control of HIV epidemic in Tianjin.