Objective: The purpose of this paper is a performance assessment of health system in IRAN based on its financial function. The measurement of achievement in fairness of financial contribution starts with the concept of a household’s contribution to the financing of the health system. The health financial contribution of a household is defined as the ratio of total household spent on health to its income above subsistence. Method: The distribution of households’ financial contribution is calculated using household survey data which includes information on income (individual level) and household expenditure (by goods and services including health).To allow for comparisons of the fairness of financial contribution, the distribution of health financial contribution across households has been summarized using an index that known as Fair Financial Contribution (F.F.C.I.). Findings: This research shows that in 2002 FFCI in IRAN was 0.815 and there were more than 3.9 percent of population, under catastrophic expenditure. we applied econometrical instrument to analysis the characters affect the risk of catastrophic expenditure. Result: This analysis shows that the insurance protection has a meaningful effect on this risk.