The degree distribution of Fountain Codes has a very important influence on Fountain Codes decoding process. So optimizing the Fountain Codes degree distribution is very significant. In this paper, we present a new way to design the degree distribution with the idea of combining several different degree distributions and integrating them to one degree distribution, namely combined degree distribution. The combined degree distribution can combine the advantages of several degree distributions. It will highly improve the performance of encoding and decoding. Through simulation experiments, we have achieved the best switch point and verified its better performance.