BACKGROUND: Primary care doctors in Shenzhen, China are increasingly expected to identify and prevent depressive disorder; however, they have received limited mental health training and community healthcare centres (CHC) do not provide standardised protocols for the diagnosis and care of depressive disorder. The World Health Organization's mental health gap intervention guide, version 2 (mhGAP-IG.v2) is a decision support tool for non-specialists for the assessment, management and follow-up of mental, neurological and substance use disorders (including depressive disorder). Given that mhGAP-IG.v2 is a generic tool, it requires adaptation to take account of cultural differences in depression presentation and unique characteristics of China's emergent mental health system. METHODS: A two-round, web-based, Delphi survey was conducted. A panel of primary care doctors from Shenzhen, were invited to score their level of agreement with 199 statements (arranged across 10 domains) proposing changes to the content and structure of mhGAP-IG.v2 for use in Shenzhen. Consensus was predefined as 80% panelists providing a rating of either "somewhat agree/definitely agree", or "definitely disagree/somewhat disagree" on a five-point scale for agreement. RESULTS: 79% of statements received consensus with a mean score of 4.26 (i.e. "somewhat agree"). Agreed adaptations for mhGAP-IG.v2 included:- an assessment approach which considers a broader spectrum of depression symptoms and reflects the life course of disease; incorporating guidance for screening tool usage; clarifying physicians' roles and including referral pathways for intersectorial care with strong family involvement; aligning drug treatment with national formularies; stronger emphasis of suicide prevention throughout all sections of the guide; contextualizing health education; reflecting a person-centred approach to care. Panelists chose to maintain diagnostic and treatment advice for bipolar patients experiencing a depressive episode as in the current guide. CONCLUSIONS: An adapted mhGAP-IG.v2 for depression recognises China's cultural and contextual needs for assessment guidance; unique primary healthcare system organization, priorities and treatment availability; and diverse psychosocial educational needs. An adapted mhGAP-IG.v2 could both inform the future training programs for primary care in Shenzhen and also offer an additional mental health resource for non-specialists in other countries.