Objective To explore the distribution patterns of the elderly in-hospital patients in the number and type of multi-morbidity. Methods A total of 5 505 elderly hospitalized patients with multi-morbidity in our hospital from 2008 to 2013 were recruited and retrospectively analyzed. Their general condition and multi-morbidity were collected and analyzed. The patients were allocated into 3 groups according to their age: low old (65 to 74 years old), median old (75 to 84 years old) and high old (≥85 years old) aged groups. Results There were 3 772 males and 1733 females included, with age ranging from 65 to 104(80.7±6.4) years. The numbers of their diseases ranged from 2 to 23. The patients with 5 to 9 types of diseases accounted for 56.76% (3 125/5 505). The most common type of multi-morbidity was cerebrovascular disease (58.31%), followed by hypertension (52.97%), infective disease (51.57%), coronary heart disease (41.11%), diabetes (30.55%), heart failure (28.45%), renal disease (23.67%), bone and joint disease (21.91%), tumor (17.31%) and gastrointestinal disease (16.17%) in order. While for different age groups, infective disease was more common in ≥85 years patients than in＜85years patients (78.89% vs 27.15%, P＜0.05). Conclusion Most elderly patients with multi-morbidity have 5 to 9 types of diseass. Cerebrovascular disease, hypertension, infective disease, coronary heart disease, and diabetes are the most common diseases in this cohort. Their multi-morbidity has age diversity. Infective disease is more common in patients over 85 years.