Abstract: What is descussed in this paper is how to reduce the gap between rapid processing power of CPU and long latency of disk access in designing a high performance Web server. First, discussed are pros and cons about current Web server models, including multi process model, multi threaded model, single process event driven （SPED）, and asymmetric multi process event driven model （AMPED）. Then an asynchronous single process event driven （ASPED） model is presented. ASPED integrates the idea of asynchronous I/O and the advantages of SPED and AMPED. It improves the I/O processing of the file systems by changing the blocking of accessing disks to nonblocking, thus avoiding the Web server’s suspending because of the blocking which leads to the idling of the CPU. In order to show the advantages of this new model, a Web server-Jaguar is implemented based on ASPED. Through SpecWeb99 testing, the performance of Jaguar is higher than that of the Web server Flash based on AMPED by up to 20%.