关键词: 服务质量（QoS）全局优化, 蚁群算法, 遗传算法

Abstract: With the applications of composite Web service becoming universality，the importance of QoS optimization problems is becoming increasingly evident.Genetic algorithm and ant colony algorithm both belongs to the QoS global optimization methods.For ant colony algorithm easy to drop into the slow pace of convergence while genetic algorithm easy to fall into local optimal solution and the low efficiency problems，the paper combines with two algorithms’ advantages，gives full play to the positive feedback characteristics of ant colony algorithm and genetic algorithm’s rapid global search capability，improves the global optimization algorithm’s ability，better resolves the Web services QoS optimization problem.

Key words: global optimization method of quality of service, ant colony algorithm, genetic algorithm