Abstract: Objective To study medical material expenditure and its impact factors amomg inpatients with medical in surance for scientific management and rational use of medica lmaterial and the reduction of medical cost.Methods Retro spective study was conducted based on a random sample of hospitalized patients with medical insurance from 2003 to 2007 in Tianjin city.Results The proportion of medical materials in medical costraised year by year(11.11%,12.68%, 14.99%,16.44%,16.14% from 2003 to 2007,respectively,F=82.33,P < 0.05).Medicalmaterial expenditure perpatient was 1115.62,1294.47,1509.95,1684.51,and 1821.11 RMB Yuan from 2003 to 2007,respectively,with a total growth of 63%(F=163.79,P < 0.05).The proprotion of personal-paid medical material,however,showed an obviously decreased trend after the modulation of medical in surance policy since 2005.The type of hospital,the duration and tmies of hospitaliza tion a ffected the cost of the medical material greatly.Conclusion Medical material expenditure for inpatient increased year by year.Hospital type,duration and tmies of hospitalization affect the cost of medical material of the inpatients.