Objective To synthesize the effects of educational intervention on the screening rate of first-degree relatives of cancer patients. Methods A total of eight Chinese and English databases were searched (PubMed, Embase, Cochrane Library, CINAHL, Web of Science, Scopus, Medline and China Biology Medicine disc) from the time of library establishment to June 2023, for randomized controlled trials investigating the effects of educational intervention on screening rate of first-degree relatives of cancer patients. Two researchers independently screened and evaluated the quality of studies. RevMan 5.3 software was used to calculate the pooled effect size. Results Thirteen studies involving 5628 participants were chosen to include in the meta-analysis. The results revealed that health education can increase screening rate of first-degree relatives of cancer patients (RR = 1.39, 95% CI = 1.16–1.65, P = 0.0002). The effect shown after short-term follow-up (≤6 months) was insignificant in terms of improving screening rate (RR = 1.46, 95% CI = 0.94–2.26, P = 0.09), but after long-term follow-up (>6 months) the improvement was greater (RR = 1.37, 95% CI = 1.13–1.65, P = 0.002). Conclusion Health education is effective in increasing the screening rate of first-degree relatives of cancer patients. The effect is more evident after long-term than short-term follow-up.