This paper studies the chaotic dynamic behavior of MPEG-4 video trace and the relationship between the chaotic dynamic characteristic and the QoS parameter. The main research motive is to analysis and to verify the inherent character of MPEG-4 video, and to investigate whether it associates with QoS. The power spectral density estimation of the video trace describes its 1/fβ and periodic characteristics. The principal components analysis of the reconstructed space dimension shows only several principal components can be the representation of all. The correlation dimension proves its fractal characteristic. The video trace is divided into many parts whose largest Lyapunov exponent values, which can be called largest Lyapunov exponent spectrum, are separately calculated using the small data sets method. The largest Lyapunov exponent spectrum shows there exists abundant chaos in MPEG-4 video. Through the comparison of the largest Lyapunov exponent spectrum and the packet loss ratio when transporting the video, the conclusion that there exists certain strong relation between them can be made. The conclusion is significant in QoS constrained video transport.