•A novel cavity with two rotary waveguides for efficient heating is developed.•The gradient descent method is used to improve the uniformity of heating object.•An experimental system is established and the simulation results are verified.•Under this method, the shape, position, and material of the object are discussed. This study aims to improve the efficiency and uniformity of microwave heating based on a rotary radiation structure. This study’s steps are summarized as follows. First, using the finite element method in a simulation model, two radiation ports revolve on their axes and heat the material. Second, the heating efficiency at different angles is analyzed to find efficient angles of radiation ports. Finally, to improve the uniformity of material with high efficiency, we use the gradient descent method in machine learning to optimize the heating time at selected angles. An experimental system is established for this research and the simulation results are verified by experiments, showing that this research has an obvious superiority and efficiency and uniformity of the material have improved compared to traditional heating results without angle selection and optimization of the heating time. What is more, influences of material with different shapes, positions and materials have also been discussed.