BACKGROUND Cancer patients not only experience a variety of problems associated with the treatment of their disease but also a range of psychological problems such as anxiety and depression, which may lead to reduced adherence to treatment and a lower quality of life for cancer patients. Telehealth interventions are widely used for cancer patients, and their effectiveness in improving anxiety and depression in cancer patients is variable and still contradictory. METHODS Embase, Pubmed, Web of Science, PsycINFO, CINAHL Complete, and the Cochrane Central Register of Controlled Trials were searched from inception to 19 April 2022. Data synthesis was conducted using STATA 15.0, and scores for anxiety and depression were calculated using standardized mean differences and 95% confidence intervals. RESULTS A total of 13125 cancer patients from 68 randomized controlled trials were included in the systematic evaluation. The meta-analysis showed that the telehealth intervention had a significant effect on anxiety (standardized mean differences = -0.40, 95% confidence intervals: -0.6 to 0.2, p < 0.001) and depression (standardized mean differences = -0.48, 95% confidence intervals: -0.67 to 0.28, p < 0.001) in patients with cancer. CONCLUSIONS Telehealth interventions significantly improved anxiety and depression levels in cancer patients compared to traditional care interventions. Breast cancer patients most often received telehealth interventions; electronic device-based and application-based telehealth interventions were more effective than online interventions; short-term interventions were more effective than medium-term and long-term interventions, and different outcome measurement tools led to different intervention outcomes. More high-quality research is needed to explore the effects of telehealth interventions.