The prevalence of chronic physical disease comorbid depression is increasing year by year. This paper discusses the current situation and influencing factors of chronic medical disease comorbid depression from the perspective of biology， psychology and sociology， involving genetics， immunity， social and family environment. Against the backdrop of rapid development of digital technology， combining medication， physical and psychological therapy to establish an intervention model of liaison consultation is expected to reduce depression in patients with chronic physical diseases and improve their overall level of physical and mental health.