Objective To investigate the inpatient’s disease and cost constitution of the Third People’s Hospital of Chengdu in 2009, so as to provide baseline data for further research. Methods The case records of inpatients in the Third People’s Hospital of Chengdu in 2009 were collected, and based on the first diagnose, the diseases were classified according to the International Classification of Diseases (ICD-10). The data including general information of the inpatients, discharge diagnosis and hospitalization expense etc. were rearranged and analyzed using Excel software. Results a) The total number of inpatients was 1 220, and male was more than female. The disease spectrum included 12 categories. b) A total of 1 093 inpatients suffered from the top 3 systematic diseases as follows: trauma and toxicosis, musculoskeletal system and connective tissue disorders, and the factors affecting health and resulting from contact with health care institutions. Except the musculoskeletal system and connective tissue disorders, the other 2 systematic diseases were mostly seen in male rather than in female. c) According to ICD-10, the top 9 diseases of trauma and toxicosis were injuries to the wrist and hand, injuries to the hip and thigh, injuries to the knee and lower leg, injuries to the shoulder and upper arm, injuries to the lower back, lumbar spine and pelvis, injuries to the elbow and forearm, injuries to the thorax, injuries to the neck and injuries to the ankle and foot; the top 4 diseases in musculoskeletal system and connective tissue disorders were dorsopathies, soft tissue disorders, arthrosis, and osteopathies and chondropathies; among the factors affecting health and resulting from contact with health care institutions, removal of fracture fixation device. d) According to ICD-10 (list of three-digit catalogue and four-digit sub-catalogue), the top 5 single diseases in trauma and toxicosis were muscle and tendon injuries of the wrist and hand, intertrochanteric frature, fracture of the femoral neck, fracture of the tibia and fibula, and fracture of the lumbar spine; the top 5 single diseases in musculoskeletal system and connective tissue disorders were lumbar disc herniation, spondylosis, arthrosis of the knee, osteoporosis with pathological fracture, and osteonecrosis. e) The average hospital stay were 23.55 days, and the average cost per capita were 13 073.73 yuan which were constituted by material cost, drug cost including western and Chinese medicines, treatment expenses including blood transfusion fee, operation expenses including anesthetic fee, examination expenses including radiation fee and laboratory fee, bed fee and others. The inpatient costs were mainly at patient’s own expense, nearly a half of those expenses were paid by social security, and public medical care only accounted for less than 3% of the total payment. Conclusion In 2009: a) The male inpatients were mainly the young and middle-aged, and the female were the elderly. The main 3 systematic diseases were trauma and toxicosis, musculoskeletal system and connective tissue disorders, and the factors affecting health and resulting from contact with health care institutions. Except the musculoskeletal system and connective tissue disorders, the other 2 systematic diseases were mostly seen in male rather than in female. b) The top 3 single diseases were lumbar disc herniation, muscle and tendon injuries of the wrist and hand, and intertrochanteric fracture. Except lumbar disc herniation, the other 2 single diseases were mostly seen in male rather than in female. c) The average hospital stay was 23.55 days. The overall costs were mainly constituted by material and drug cost (59.25%), with rationality worthy of attention. d) Inpatient costs were mainly at patient’s own expense or paid by social security, and the proportion of public medical care was low in the payment.