Abstract: In this paper, we observed and measured the chaotic phenomena in a circular Couette flow system by means of flow visualizations arid Laser light scattered power spectra.Two routes to turbulence have been found: the first one viafrom quasiperiodic motion to chaos, the second one via intermittency.A new idea that the weak nonlinear,interaction may locally have an effect on Taylor vortices is introduced in explanation of the great difference in transition threshold values between the Above two routes.