Analytical research was conducted to study the heat transfer from horizontal surfaces to normally impinging circular free-surface jets under arbitrary-heat-flux conditions. General expressions of heat transfer coefficients and recovery factor were obtained in the stagnation region and boundary layer region as well as viscous similarity region by the integral method. Then by using the analytical results, the conjugated heat transfer between a water jet and the impinged wall was numerically solved. Finally, an experimental study was also performed to characterize conjugated heat transfer coefficient on a thick copper target base impinged normally by circular free-surface jet. The present predictions of the mean conjugated heat transfer coefficient were good agreement with the experimental data.