Men who have sex with men (MSM) are a hidden but emerging population susceptible to HIV infection against a background of rapidly increasing HIV prevalence in China. Low HIV testing levels and multiple partnerships among MSM are two major contributing factors to HIV transmission. Methods: We conducted a cross-sectional survey among 447 Chinese MSM in Changsha and Tianjin cities from November to December 2011 using an anonymous questionnaire. We aim to investigate (1) the trend of HIV testing rates among Chinese MSM during 2009 to 2011; and (2) the patterns of multiple sexual relationships with male, female and commercial partners. Results: The self-reported past-12-months HIV testing level among Chinese MSM increased from 16.6 in 2009 to 46.3 in 2010 and 58.6 in 2011 (?2 = 173.49, p <0.001). Compared with men who have tested for HIV, the never-tested MSM were generally younger, never married, students, and more likely to have unprotected anal intercourse with non-commercial male partners. Furthermore, 21.3 (56/263) MSM reported having multiple regular male and female sexual partnerships and 6.2 (16/257) reported having commercial male partners in the past six months. However, individuals who were never-tested for HIV are consistently less likely to engage in multiple sexual relationships.Conclusions: HIV testing rates have increased substantially among Chinese MSM in the period 2009-2011, although significant barriers to testing remain. Multiple sexual partnerships, and especially bisexual behaviours, are common among Chinese MSM. ? 2013 Chow et al.; licensee BioMed Central Ltd.