This paper presents the experimental and numerical results of the bubble detachment from a submerged orifice at a constant gas flow rate. The compressible large eddy simulation combined with the volume of fluid method is adopted in the simulation and is validated by experiment. The transition criterion from the elongation stage to the detachment is obtained. In the detaching stage in the simulation, the distributions of the pressure and the surface tension on the cylindrical bubble neck are obtained. The Rayleigh-Plesset equation in the cylindrical coordinate frame is used to describe this process. Based on the comparison between the numerical results and the equation analysis, a reference value of the uncertain integral parameter in the equation is determined.