An ultra-thin vapor chamber (UTVC) is an efficient heat transfer component that meets the heat dissipation requirement of miniaturized electronic devices. Heat dissipation is one of the most important issues for UTVCs. With decreasing thickness, the mechanical strength of heat pipes and vapor chambers drops dramatically, and inevitable surface damage occurs during conventional contact thermal testing. Here, we demonstrate a non-contact thermal testing method using laser heating and infrared temperature measurement to evaluate the thermal performance of UTVCs. This non-contact method allows UTVCs to reach a steady-state sooner than traditional contact methods. Use of the characteristic thermal resistance is proposed for more straightforward evaluation of the UTVC thermal performance in non-contact testing setups. This non-contact thermal testing method has proved to be an efficient testing method for UTVCs due to its rapidity, accuracy, and non-destructiveness.