Abstract: The data of Xin Jiang Turpan 20 MW（p） PV power plant dust loss were analyzed; the experimental data indicated that power generation enterprises（PGE） dust loss has the linear relationship with time.The linear cleanliness management model for thermal power plant condenser is used to analyze dust loss and optimal cleaning cycle with the purpose of minimizing per unit time economic loss.The example results showed that when the average light intensity is 230 W/m~2,the optimal cleaning cycle of 500 kW（p） PV modules array in 20 MW（p） PV power plant with mechanical cleaning mode is 3.40 d.Comparing to the current operating cleaning cycle of 15 d,the optimal cleaning cycle of 3.40 d can save the cost of dust for about 721.00 thousand·a^-1 in 20 MW（p）PGE.