Focused on the issue that the wireless real-time transmission network of HD (High Definition) video has characteristics of long delay, a dynamic scheduling mechanism based on Enhanced Hybrid Coordination Function (EHCF) was proposed. In this mechanism, firstly, truncation and extension of beacon interval were used to adapt to the burst of the video data. Then, the transmission needs of each station were determined by its cache size of the video data, and accordingly, the priority of the station was defined. Next, the threshold of transmission needs and differences were applied to evaluate the weights of transmission needs of the high priority stations. Finally, the channel resource was allocated according to the assessment. A comparison with traditional Hybrid Coordination Function (HCF) was made according to H.264-based video transmission simulations with 22 Mb/s and same number of stations. The result shows that there is a significant improvement on delay, ranging from 54.3% to 87.6%. The theoretical analysis and simulation results show that the EHCF mechanism can effectively improve the delay of network in wireless video transmission.