In this paper, we propose an efficient encoding solution for the screen-sharing applications with multiple clients connected. We first present a lightweight screen codec to compress the complicated screen content. Based on the architecture of the proposed codec, we propose a one-pass encoding algorithm for multiple bit-rates. The one-pass encoding algorithm enables the host to only involve in one-pass encoding process for multiple bitrates, and as a result the computation complexity of the host is decreased significantly. Specially, in the limited computing-resource case, the one-pass encoding algorithm can improve the screen-sharing performance by about 43%, in terms of framerates the clients can get. In addition, based on our codec, we propose a fast screen transcoding scheme for the data-center based screen-sharing applications.