HTTP adaptive streaming technology is the forefront key technology for multimedia video transmission.However,it is still a challenge how to switch video bitrates under time-varying bandwidth.In this paper,we propose a novel control algorithm using in HTTP adaptive streaming technology.We formulate this bitrates control scheme as decision-bitrates strategy.The algorithm uses network sliding window and two-way logistic equations.The objective is to calculate the optimal video bitrates.Furthermore,we design decision-bitrates controller to improve its adaptation performance and maximize the playback quality.Numerous experimental results demonstrate: the proposed algorithm could dynamically adjust video bitrates under time varying bandwidth and reflected excellent stability and universality.