In the microwave hyperthermia field, maximizing the energy absorption over irregular-shaped tumor regions within the human body and avoiding hot spots in the surrounding normal tissues are challenging tasks. In this paper, we propose a non-invasive tumor hyperthermia method, which is based on the angular spectrum projection field shaping theory, to effectively control the magnitude distribution of the electric field in the observation plane and focus the energy absorbed by the target tissue. The proposed method could also effectively deposit the microwave energy to the irregularly shaped tumors. The effectiveness of the method is primarily verified by several full-wave simulations with a simplified human tissue model consisting of planar stratified layers.