Despite favorable effects from telemedicine (TM) on cardiovascular diseases, outcome and comparative impact of TM on heart failure (HF) adults remain controversial. A meta-analysis was conducted to summarize the evidence from existing randomized controlled trials (RCTs) which compared potential impact of TM on HF with conventional healthcare. TM mainly included structure telephone support (STS), involving interactive vocal response monitoring and telemonitoring. PubMed, MEDLINE, EMBASE, and the Cochrane Library were searched to identify RCTs to fit our analysis (1999 to 2018). Odds ratio (OR) with its 95% confidence interval (CI) was used. Sensitivity analysis, subgroup analysis, and tests for publication bias were conducted. Heterogeneities were also evaluated by I<sup>2</sup> tests. A total of 29 RCTs consisting of 10,981 HF adults were selected for meta-level synthesis, with follow-up range of 1-36 months. Telemonitoring is associated with the reduction in total number of all-cause hospitalization (OR 0.82, 95% CI 0.73-0.91, P = 0.0004) and cardiac hospitalization (OR 0.83, 95% CI 0.72-0.95, P = 0.007). Telemonitoring resulted in statistically significant risk reduction of all-cause mortality (OR 0.75, 95% CI 0.62-0.90, P = 0.003). However, the OR of HF-related mortality (OR 0.84, 95% CI 0.61-1.16, P = 0.28) is not significantly distinguishable from that of conventional healthcare. Receiving STS interventions is likely to reduce the hospitalization for all causes (OR 0.86, 95% CI 0.78-0.96, P = 0.006, I<sup>2</sup> = 6%) and the hospitalization due to HF (OR 0.74, 95% CI 0.65-0.85, P < 0.0001, I<sup>2</sup> = 0%), compared with interventions from conventional healthcare. OR of all-cause STS mortality (OR 0.96, 95% CI 0.83-1.11, P = 0.55) was identified in meta-analyses of eight cases. OR of STS cardiac mortality (OR 0.54, 95% CI 0.34-0.86, P = 0.009) was identified in meta-analyses of three cases. This work represents the comprehensive application of network meta-analysis to examine the comparative effectiveness of telemedicine interventions in improving HF patient outcomes. Compared with conventional healthcare, telemedicine systems with medical support prove to be more effective for HF adults, particularly in reducing all-cause hospitalization, cardiac hospitalization, all-cause mortality, cardiac mortality, and length of stay. While further research is required to confirm these observational findings and identify optimal telemedicine strategies and the duration of follow-up for which it confers benefits.