Objective To understand the perceptions and evaluations of pediatric residency trainees and supervising physicians regarding the implementation environment of residency training, analyze existing problems in the training implementation, and provide evidence for optimizing the implementation of residency training. Methods From January to February 2024, using cluster sampling method, 118 residents who entered the pediatrics base and pediatric surgery base from 2021 to 2023 and 70 supervising physicians at the Children′s Hospital of Fudan University enrolled in the study. A convergent parallel mixed-methods design was adopted. The quantitative research portion employed a questionnaire survey, with data analysis using t-tests, latent profile analysis, chi-square tests, and univariate analysis. The qualitative research used maximum variation sampling to select 20 residents and 8 supervising physicians from the quantitative study for one-on-one semi-structured interviews. Results A total of 115 residents and 65 supervising physicians participated in this study. The resident trainees and supervising physicians scored (60.04±9.88) and (62.57±7.47) points respectively for their perception of the residency training implementation environment (with a maximum score of 80 points for both), and the difference was not statistically significant (P=0.110). The resident trainees scored lower than the supervising physicians in both the work dimension and learning dimension [(3.44±0.77) vs. (4.14±0.43), (3.58±0.85) vs. (3.98±0.58)], and the differences were statistically significant (all P<0.001). The perception scores of resident trainees for the residency training implementation environment were divided into 2 categories: high perception group [53.0% (61/115)] and low perception group [47.0% (54/115)]; the perception scores of supervising physicians for the residency training implementation were divided into 3 categories: high perception group [30.8% (20/65)], low perception group [55.4% (36/65)], and extremely low perception group [13.8% (9/65)]. The comparison of the number of resident trainees in different perception categories by their affiliated training base showed a statistically significant difference (P=0.002), with more trainees from the pediatric surgery base in the high perception group than in the low perception group (20 vs. 5). The comparison of professional titles among supervising physicians in different perception categories showed a statistically significant difference (P=0.041), with more supervising physicians holding the title of chief physician in the low perception group than in the high perception group (13 vs. 2). Based on the interview results, four themes were extracted: diverse and rich training content and formats; insufficient allocation of work facilities and equipment; high workload with lack of incentive mechanisms; research pressure exists but research support is insufficient. Conclusions From the perception among resident trainees and supervising physicians, the implementation environment of residency training requires enhancement, with work conditions, learning opportunities, and research support being the primary areas needing improvement. A refined institutional support system should be established to balance clinical work, learning, and research in residency training, and the residency training implementation plan should be optimized according to the perception category characteristics of residents and supervising physicians.