The housing expenditure of the tenants of National Rental Housing Program should be targeted within the range of affordability in order for the program to achieve its own policy goal of securing the affordable housing of the low-income household. Evaluating the affordability of the current housing program, this paper estimates the affordable housing expenditure of typical tenants of the type I, II, and III National Rental Housing using the Household Consumption (Survey) Data, and compares it with the actual housing expenditure by the standard deposit and rent of National Rental Housing. It was founded that the housing expenditures of the type I, II, and III National Rental Housing exceed the affordable housing expenditures of the tenants by \35,400, \67,200, and \166,200 respectively for each type. As alternative amendment that can make the housing program affordable, this paper suggests a rental-aid policy and deposit-aid policy. If a rental-aid policy is adopted, it is estimated that \593 billion of additional finance is needed for the next 10 years. If a deposit-aid policy is adapted, it is estimated that \390 billion of additional finance is needed for the next 10 years.