Nowadays VoIP (Voice over IP) develops quickly. H.323 is the most popular and mature architecture for VoIP, in which Gateway is one of the most important components. In this paper, two main aspects of the Gateway are discussed. They are the processing of simultaneous initialization of multiple calls and the compatibility with other H.323 standard endpoints and different H.323 versions. At last, the test of our Gateway is shown and the result is discussed.