Objective To explore the impact of community medicine internship on medical students′ cognition of and interest in primary healthcare, and their willingness to work in primary healthcare. Methods A survey was conducted using a self-designed questionnaire. From November 2023 to June 2024, 142 medical students from Zhejiang University who participated in the community medicine internship enrolled in the study, and surveys were conducted before and after the internship respectively. Data were analyzed using the Mann-Whitney U test, χ² test, and Spearman rank correlation analysis. Results The total score of medical students′ cognition of primary healthcare increased from 22.0 (20.5, 24.0) before the internship to 28.0 (27.0, 28.5) after the internship, with a statistically significant difference (P<0.05). The proportion of medical students interested in primary healthcare increased from 52.7% (49/93) before the internship to 67.4% (95/141) after the internship, with a statistically significant difference (P<0.05). The proportion of medical students willing to work in community health centers increased from 39.8% (37/93) before the internship to 48.2% (68/141) after the internship, and the proportion willing to engage in general practice increased from 40.9% (38/93) to 50.4% (71/141) after the internship; these differences were not statistically significant (all P>0.05). The Spearman correlation coefficient between medical students′ primary healthcare cognition and interest was 0.289 before the internship and increased to 0.636 after the internship (all P<0.05). Conclusions Community medicine internship improved medical students′ cognition of and interest in primary health care, and strengthened the positive correlation between the two factors, but it did not have a significant impact on their willingness to work in primary healthcare.