Abstract: The phenomenon of droplet entrainment caused by bubble rupture at the free liquid surface exists widely in water-cooled reactors. Under accident conditions, the aerosol detained in the liquid pool can be transferred into the air by entrainment. Accurate calculation of the release amount is an important basis for the evaluation of the source term. The final release characteristics are directly determined by parameters such as bubble lifetime, liquid film thickness, and droplet size etc. Owing to complex and random process of bubble rupture, there is no universally applicable method for measuring the crucial parameters of bubble rupture on the liquid surface, and the results are not applicable to each other. This brings great difficulties to the evaluation of the release characteristics of the final source term. In order to investigate this phenomenon, the measurement methods of the above physical parameters and some empirical formulas were summarized. The applicable scope of different methods was compared. Finally, various measurement schemes and subsequent research directions for bubble rupture behavior were summarized and prospected.