Abstract
With an increasing number of College Admissions activities, education and scientific researches organized by universities, it is of prominent importance for newcomers to get help from campus navigation. And smart phones being more popular, it is possible to solve the above problem. During the process of setting up one kind of campus navigation system, the thesis improved the basic A algorithm: using bidirectional search in the basic implementation of A algorithm and adding a path cache function and an anticipation mechanism. Path cache made full use of the paths which had been calculated by A algorithm to decrease the delay of figuring out the path. To a large extent, it accelerates the server's response and increases the throughput of the server.