Abstract: A self-constructed Tee-mixer experimental system was established. Glycerol-water solution with a glycerol mass fraction φ of 80%, pure glycerol, and water were used as simulation media. Under the conditions of a core flow initial superficial velocity U_g,100 ranging from 0.6 to 1.9 m/s and two annular flows with apparent viscosities μ_w = 1.0×10⁻³ Pa·s and μ_g,80 = 1.8×10⁻² Pa·s, a high-speed camera was employed to capture the flow pattern evolution of the core fluid. Combined with CFD numerical simulation, the effects of U_g,100 and annular flow apparent viscosity μ on transport stability of core annular flow were systematically investigated. The results show that increasing U_g,100 had no significant effect on the transport stability of the core flow when Re_g,100 > 3.4. For the core flow with Re_g,100 = 3.4, the peak amplitude of the dimensionless annular upper spacing L₁ within the frequency range of 0 ~ 500 Hz was 0.8×10⁻¹. For the core flow with other Re_g,100 values, the L₁ amplitudes remained within 0 ~ 0.6×10⁻¹, the peak values of the power spectral density (PSD) curves were relatively small, and the spectral widths ranged from 4.1×10⁻⁸ to 3.3×10⁻³. Increasing μ effectively suppressed oscillations of the core flow and enhanced transport stability. When the annular flow Reynolds number Re_g,80 was 9.1×10², the amplitude distribution of L₁ within 0 ~ 50 Hz was only 0 ~ 6.0×10⁻², and the PSD spectral width was as low as 10⁻⁷ ~ 10⁻⁵. When the annular flow Reynolds number Re_w was 1.5×10⁴, the amplitude oscillation range of L₁ within 0 ~ 50 Hz was 0 ~ 6.0×10⁻², and the PSD spectral width was approximately 10⁻⁷ ~ 10⁻³. This study provides a basis for optimizing annular flow mixing and transport processes.