Abstract: This paper presents a transmission rate control mechanism in cloud computing environment for mobile video.The combination of mobile and cloud computing, which has a powerful computing and storage capacity, improves the performance of the mobile device.First, the proposed mechanism algorithm can forecast bandwidth by using hidden markov chain.Then using the relationship between hardware and bit rate, the mechanism adjusts bit rate adaptively.On this basis, we design a buffer management algorithm to improve accessing hit rate.Our simulation results demonstrate that the proposed mechanism achieves significant improvement in terms of QoE and network resource utilization.