This paper focuses on the problem of data missing under non-random missing mechanism. Under the assumption that the population distribution follows two-parameter Gamma and the probability of success was exponential distribution,the parametric estimation and quantiles of two-parameter Gamma distribution model were obtained via moment method and iterative computation. Simulation studies were carried out using R language,when the missing ratio takes value 0. 2 and 0. 5 respectively. The simulation results were...