Adaptive Streaming over HTTP (DASH) transmission protocol based on HTTP can enable users to select suitable video quality according to their terminal display capabilities and channel conditions, which is the development direction of network video service technology. How to adaptively select the video bit rate to obtain the best Quality of Experience (QOE) according to the change of network throughput has not been well solved in the existing DASH systems. In this paper, an adaptive transmission algorithm based on fuzzy control is proposed, which takes the buffered video time and the bitrate mismatch between the video bitrate and the network throughput as input and the expected buffer change as output. Fuzzy logic is used to achieves the following control objectives: (1) The buffered video time stays within a safe range; (2) the average quality of the transmitted video is maximized, and (3) the video playback interruption caused by bandwidth fluctuation is avoided. Finally, performance tests were conducted in two virtual network environments and two actual network environments. The experimental results show that the proposed algorithm is superior to traditional algorithms in terms of QOE.