Objective To understand the training effect and needs of trainees at Beijing Daxing District General Practitioners (GPs) Transfer Training Base, and to provide reference and guidance for the follow-up GPs transfer training. Methods This study was a cross-sectional survey and 68 participants who had completed clinical training at the Beijing Daxing District GPs Transfer Training Base from 2019 to 2021 were selected. According to "the General Practitioner Transfer Training Outline" and "the Beijing General Practitioner Transfer Training Rules", we compiled test papers, organized unified assessment, and statistically analysed the results and the influencing factors. A questionnaire survey was conducted to understand the basic situation and training needs of the trainees. Results The average total score of the trainees was (125.0±9.8) points with a pass rate of 95.5%, and the difference in scores between trainees with different educational backgrounds was statistically significant (P＜0.05). In the single module, the correct answer rates of "community rehabilitation", "common knowledge and skills in ophthalmology" and "common knowledge and skills in rehabilitation " were more than 60%, while "community common chronic disease management", "preventive medicine", "common knowledge and skills in endocrinology" and "common knowledge and skills in kidney medicine" were zero. Eighty-eighe point two percent of the trainees thought that the training was more helpful to their clinical work and that they could apply the training knowledge and skills to actual clinical work with high frequency, but there were differences among trainees of different ages and years of working experience (all P＜0.05). The training method recognised by 66.2% of the trainees was case discussion, and 69.1% of the trainees considered that the most needed training content was the diagnosis and treatment of common and frequent diseases. Conclusion Trainees are generally qualified in general practice, but modules such as the management of common chronic disease and preventive medicine need to be strengthened. It is recommended that training bases should design training programs oriented to the needs of trainees, and that training should be conducted at different levels to improve the effectiveness of training.