Hydrodynamic and heat transfer characteristics of the circular hydraulic jump by air-assistant water jet impingement was experimentally investigated using water and air as the test fluid. The effects of volumetric quality (beta = 0-0.9) on the hydraulic jump radius, local Nusselt number and, pressure at the stagnation point were considered under fixed water-flow-rate condition. The results showed that the dimensionless hydraulic jump radius increased with volumetric quality, attained a maximum value at around 0.8 of the volumetric quality, and then decreased. The hydraulic jump of two phase impinging jet is governed by the stagnation pressure and the lateral variation of Nusselt number is governed by hydraulic jump radius. Based on the experimental results, a new correlation for the normalized hydraulic jump radius of the impinging jet are developed as a function of the normalized stagnation pressure alone. (C) 2016 Elsevier Ltd. All rights reserved.