The extend angle is a major parameter to effect the cavitation of convergence-divergence nozzle. Applies continuity equation, momentum equation and Rayleigh-Plesset equation to the steady-state solutions of bubbly liquid through different extend angles of converging-diverging nozzle. The results show that the flow properties are affected dramatically by the extend angels and the void fraction and the bubble radius vibrate violently with the increasing of the extend angle. With large-amplitude and high-frequency oscillating near the threshold, bubble creates and collapses repeatedly, which will help to release more cavitation energy.