The problem of data loss is an important research topic in the grid dispatching and control system. A new method based on genetic optimization for dealing with missing data is proposed to ensure the data integrity and accuracy. The proposed method can estimate incomplete data parameters by genetic optimization algorithm. According to the optimal parameters, the Markov Chain Monte Carlo algorithm is used to estimate the missing data. Through filling the incomplete data in the grid dispatching and control system, it is discovered that the proposed method can find more missing data within the same time duration and improve the accuracy of estimated values which guarantee the data integrity and accuracy.