Although ambient temperature has been linked with injury incidence, there have been few nationwide studies to quantify the temperature-related risk and burden of cause-specific injury hospitalizations. Additionally, the impact of human-induced climate change to injury burden remains unknown. Our objectives are to examine the associations between ambient temperature and injury hospitalizations from various causes and to quantify the contribution of human-induced warming to the heat-related burden. We collected injury hospitalization data from a nationwide hospital-based registry in China during 2000–2019. Using a time-stratified case-crossover design, we investigated the associations between daily mean temperature (°C) and cause-specific injury hospitalizations. We also quantified the burden of heat-related injuries under the scenarios with and without anthropogenic forcing, using the Detection and Attribution Model Intercomparison Project to assess the contribution of human-induced warming. Our study included a total of 988,087 patients with hospitalization records for injuries. Overall, compared to the temperature at minimum risk of hospitalization (−12.1°C), the relative risk of hospitalization at extreme hot temperature (30.8°C, 97.5th percentile) was 1.18 [95% confidence interval (CI): 1.14, 1.22], with an approximately linear association between temperature and hospitalization. Vulnerability to heat-related injuries was more pronounced among males, young (<18 years of age) or middle-aged (45–64 years of age) individuals, and those living in the North. The heat-related attributable fraction increased from 23.2% in the 2000s to 23.6% in the 2010s, with a corresponding increase in the contribution of human-induced change over time. In the 2010s, the heat-related attributable fractions for specific causes of injury ranged from 12.4% to 54.4%, with human-induced change accounting for 6.7% to 10.6% of the burden. This nationwide study presents new evidence of significant associations between temperature and cause-specific injury hospitalizations in China and highlights the increasing contribution of human-induced warming to the injury burden.