Web services are the growth of distributed paradigm. In web service system the load/stress test are simulated to reduce the traffic in abnormal condition. Cognitive Metrics focus on perceptual, problem solving, decision making and analytical behaviors of the individuals. Cognitive metrics are used to measure the complexity of the system to improve its performance. Cognitive metrics in testing is to analyze the Web services risk and reduce the unclear bugs in the distributed environment. Our method to improve the reliability and quality of the distributed environment based on the stress testing tool and cognitive measures. In real world distributed system the above method defined, how the stress test case is derived and executed using stress testing tool and evaluates the system by cognitive metrics. This method pointed towards to regulate the traffic, decrease the high failure rates and reduce the complexity of the system.