Objective To construct a prenatal mental health care model and its related practice protocol under the guidance of evidence-based methodology. Methods Under the guidance of the "MRC framework for the design and evaluation of complex interventions to improve health", the evidence foundation was identified through literature review, and the prenatal mental health care model was formed through logical deduction and expert consultation. The key elements of the model were specified and integrated into the preliminary intervention path and practice protocol according to the philosophy and methods of evidence-based medicine. The practice protocol was finalized through expert consultation and simulation test. Results The established prenatal mental health care model was characterized with midwife-based and multidisciplinary cooperation, and could manage the mental health of pregnant women according to their different psychological risk levels by universal, selective and indicated intervention. During the simulation test, 4 878 pregnant women received mental health screening, accounting for 97.99% of the total pregnant women; 11.02% accessed the intervention path and received mental health services. Six pregnant women participated in the whole test process. Conclusion The model suits local situation and the compentence of the practitioner and is in line with the trend of mental health services. In order to exploit the potential of the prenatal mental health care model, it is necessary to comprehensively improve the ability of providing mental health care by obstetric professionals.