Aims Shrubland is one of the most important vegetation types in subtropical region, but studies on its life-form composition and geographic patterns are scarce. In this paper, we addressed the following questions: what are the characteristics of the composition of plant life forms of subtropical shrublands in China? And what are the relation- ships between the life form compositions, geographic patterns of subtropical shrublands and hydrothermal factors? Methods A total of 688 plots, designed with the stratified random sampling method, were systematically set and investigated in subtropical shrublands in China. Life forms were identified based on Raunkiaer's (1934) life form systems. Life form spectrums were compiled at each sampling site and within the whole shrubland, respectively. Partial correlation analysis was applied to reveal the latitudinal, longitudinal and altitudinal patterns of each life form. Pearson's correlation analysis was adopted to evaluate the relationships between each life form and hydrothermal factors. Further, redundancy analysis (RDA) was used to distinguish the effect of temperature and precipitation on geographical variations of life forms. Important findings (1) In subtropical shrublands in China, 56.37% of the total species were woody species, among which 33.88% were deciduous species and 22.49% were evergreen species. The remaining 43.63% of the total species were herbaceous species, dominated by 35.15% perennials. Generally, phaenerophytes (Ph) was the most dominant component, while the second dominant one was hemicryptophytes (H). The life form spectrum showed a pattern of Ph (55.74%) > H (31.03%) > T (therophytes 8.80%) > Cr (cryptophytes 4.08%) > Ch (chamaephytes 1.34%). (2) Plant life forms mainly exhibited longitudinal and altitudinal patterns. With the increase of longitude, the percentage of Ph tended to increase while H, Cr and T tended to decrease. Furthermore, an increase in altitude would lead to an increase in H and Cr but a decrease in Ph, Ch and T. (3) Among all the investigated climatic factors, the mean temperature of the warmest month (MWT) and the mean precipitation of the coldest month (MCP) had the greatest impact on Ph, H, Cr and T. With an increase of MWT and MCP, Ph would increase while H, Cr and T would decrease. Taken together, MWT and MCP could explain 41.97% of the variation of life form spectrum, among which 28.35% was attributed to their joint-effect. The results suggested that Ph and H were mainly influenced by both temperature and precipitation, and that Cr was more sensitive to temperature gradients. Besides, T was more sensitive to precipitation, and Ch showed little fluctuation along hydrothermal gradients. In conclusion, MWT and MCP are the most important hydrothermic factors that determine the geographic patterns of life forms in subtropical shrublands in China.