Abstract: After a long task execution on Hadoop cluster, as cluster faults would hurt Hadoop cluster on different strength, which became the main reason of cluster performance degradation and more frequent cluster faults, more serious would cause the decrease of cluster average life. To solve the problem, this paper proposes a method of Hadoop cluster average life prediction based on Poisson process. By prediction calculation, adjust and optimize the cluster timely to keep the cluster performance in a normal state. Then make several experiments on three different feature types of Hadoop cluster to observe the frequncy of cluster average life. According to the experiment results, this method is the significant to Hadoop cluster performance evaluation and optimization.