TFRC protocol is very suitable for video transmission, while quality assessment is also essential in video transmission system. In this paper a real-time video transmission system based on TFRC protocol is proposed, and an evaluation model about the system is improved in the framework of Evalid. It assesses the quality and efficiency of the video transmission according to the actual video file, and analyzes losses frame in different video types during transmission as well as the picture quality in receiver. The results of simulation experiment in NS-2 show that when real-time video transmitted in complex network environment using this system, the receiver can get satisfactory video quality by reason of the TFRC protocol friendliness and the smoothness of sending rate.