An improved combined algorithm(improved genetic hill climbing,IGHC) which utilizes the improved genetic operators to optimize Hill-Climbing is proposed. The algorithm adjusts the probability of crossover and mutation self adaptive,selects the way of crossover and mutation automatically,utilizes the crossover and mutation operators replace the edge deletion operator of HC to extend its ability of global optimization,and utilizes the Most Weight Supported Tree restrict the search space to improve search efficiency. Compared with HC and GA(genetic algorithm),the simulation results have shown that the IGHC algorithm can obtain a model more accurate and rapid,the best score of model is higher than GA and HC. Combined with cement grate cooler operating data in the process of cement clinker heat transfer,the fault diagnosis model of technological parameter can be constructed and a precise fault diagnosis of secondary air temperature in the cement grate cooler can be realized,so this algorithm has a certain practical significance.