This study aimed to compare postoperative efficacy and functional outcomes between partial sialoadenectomy (PS) and total sialoadenectomy (TS) in patients with benign submandibular gland (SMG) tumors. We systematically searched PubMed, Web of Science, EmBase, Cochrane Library, China Biomedical Literature, and CNKI from inception to 2024, following PICOS criteria (Population: Adults with benign SMG tumors; Intervention: PS; Comparison: TS; Outcomes: Salivary function, neurological complications, recurrence, operative duration, dry mouth, infection/hematoma; Study design: RCTs/observational studies with ≥ 6-month follow-up). The protocol was prospectively registered (PROSPERO CRD42024595824). Risk ratios (RR) were calculated for dichotomous outcomes, and weighted mean differences (WMD) for continuous outcomes, using random-effects models. Heterogeneity was quantified by I2 statistics and Q tests. Sensitivity analyses included leave-one-out methods, and publication bias was assessed via funnel plots and Egger's test. The analysis of findings was guided by the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) framework to evaluate evidence certainty, while also considering the size of intervention effects in alignment with GRADE methodology. From 1014 screened studies, 7 studies (3 RCTs, 4 cohort studies) involving 399 patients (PS: n = 188; TS: n = 211) were included. PS demonstrated superior static saliva flow (WMD = 0.24, 95 %CI 0.13, 0.35)and reduced neurological complications (RR = 0.22, 95 %CI 0.10, 0.49), operative duration (WMD = -14.19, 95 %CI -23.4, -4.99), and dry mouth (RR = 0.12, 95 %CI 0.03, 0.49). However, there were no significant differences between the two groups in stimulated saliva flow (WMD = 0.01, 95 %CI -0.01, 0.04), tumor recurrence (RR = 3.23, 95 %CI 0.13, 77.99), postoperative infection (RR = 0.25, 95 %CI 0.03, 2.26), and postoperative hematoma (RR = 0.36, 95 %CI 0.08, 1.72). GRADE revealed moderate-certainty evidence for functional outcomesbut low/very low certainty for neurological complications, recurrence, operative duration, dry mouth, postoperative infection and hematoma. The current results demonstrate that partial sialoadenectomy offers significant advantages over traditional total sialoadenectomy.It is recommended that clinicians consider adopting new surgical procedures for the treatment of benign tumors of the submandibular gland in the future.