In order to strengthen the level of project decision-making and risk management of the lessee and lessor and according to the characteristics of aircraft financing lease, the rent-price model of the cost change un- der uncertainty environment was constructed by the cost-plus method of the lessor, which based on Monte Carlo simulation calculation in the wave of interest rate. At the same time, considering the lessee’s rent affordability, calculating the maximum rent that the lessee afforded. Suppose that the lessor can quote the maximum rent that the lessee can afford and calculating the theoretical price of rent and probability of lessor satisfied object earning rate. The results showed that the theoretical price of rent was convergent. When the lessor quotes to the lessee, if the economic environment changes and the initial investment increases, the probability that the lessor can achieve the object earning was significantly reduced. When the lessee's revenue decreasing or cost increasing af- ter lessee accepts the lessor’s offer, the lessee will assume more risk. Therefore, the lessor should strengthen the management of the initial investment amount and the lessee should strengthen the income management and cost control.