Objective:To explore the effect of high intensity interval training (HIIT) on cardiac rehabilitation in patients after heart transplantation.Methods:According to the search terms, the search was conducted on China National Knowledge Infrastructure, VIP, WanFang Data, China Biology Medicine disc, Web of Science, PubMed, Cochrane Library, Embase, and EBSCO. The search time limit was from the establishment of the database to January 31, 2022. After 2 researchers screened the article, extracted information, and evaluated the quality, a Meta-analysis was conducted using RevMan 5.4 software.Results:According to the inclusion and exclusion criteria, 10 English articles were selected, including 191 patients in the intervention group and 212 patients in the control group, with a total of 403 patients. Meta-analysis showed that during cardiac rehabilitation exercise in patients after heart transplantation, HIIT could improve peak oxygen uptake in cardiopulmonary function exercise testing [ MD=1.98, 95% confidence interval ( CI) (0.55, 3.41), P=0.007], peak heart rate in chronotropic responses [ MD=6.93, 95% CI (2.62, 11.24), P=0.002], and muscle exercise ability [ MD=337.18, 95% CI (12.02, 62.35), P=0.04]. There was no statistically significant difference in systolic blood pressure, diastolic blood pressure, peak systolic blood pressure, peak diastolic blood pressure, resting heart rate and respiratory exchange rate between the two groups ( P>0.05). A subgroup analysis of peak oxygen uptake was conducted based on the intervention period and the start time of rehabilitation exercise after heart transplantation. The results showed that there were statistically significant differences in peak oxygen uptake between the intervention group and the control group when the intervention period was ≤ 12 weeks or the start time was > 6 weeks ( P<0.01) . Conclusions:HIIT effectively improves the peak oxygen uptake, peak heart rate, and muscle exercise activity of patients after heart transplantation. HIIT has a significant impact on peak oxygen uptake when the rehabilitation exercise start time after heart transplantation is > 6 weeks or the intervention period is ≤ 12 weeks.