Abstract: Analytical research was conducted to study heat transfer from horizontal surfaces to normally impinging circular jets under arbitrary-heat-flux conditions. The thermal and laminar velocity boundary layers were first divided into five regions of flow in a comprehensive method. Approximate expressions of heat transfer coefficient were obtained both for stagnation zone and partial wall jet zone by applying integral techniques and Mangier transition. The analytical results of the constant-heat-flux condition agree with those of both of the exact solution and numerical solution from available literature.