According to Maxwell's electromagnetic theory or classical electromagnetic theory, if there is a changing current on the antenna, an electromagnetic wave will be induced around the antenna, which can propagate in space. When the electromagnetic wave propagates to the receiving antenna, the electromagnetic wave transfers the electromagnetic energy and momentum to the receiving antenna. The receiving antenna receives the electromagnetic signal. The above discussion is the standard description of electromagnetic wave in almost all electromagnetic field textbooks. The author found this description wrong. According to Wheeler Feynman's absorber theory, the radiation generated by the transmitting antenna is not only determined by the changing current of the transmitting antenna, but also affected by the current changes of the environmental materials. The material absorbing electromagnetic wave affects the transmitting antenna by radiating the advanced wave. The author supports Wheeler Feynman's view. Maxwell's electromagnetic theory needs to satisfy the Sliver-Muller radiation condition. This condition actually describes that a good absorber material has been arranged at the far field of the transmitting antenna, which can absorb all the radiated electromagnetic waves. Considering these, the author establishes a new electromagnetic theory, in which all transmitting antennas, absorber materials are near the origin. It is assumed that no matter on the sphere with infinite radius can absorb electromagnetic waves, so electromagnetic waves cannot transmit electromagnetic energy to infinity. The author adds this idea to Maxwell's electromagnetic theory. That is to add a boundary condition for Maxwell's electromagnetic theory that radiation does not overflow the universe. This boundary condition must be in conflict with Maxwell's electromagnetic theory. Because the far field of Maxwell's electromagnetic theory can only take the Sliver-Muller radiation condition. However, the author finds that we can relax Maxwell's equation appropriately. In fact, the author relaxes the mutual energy principle equivalent to Maxwell's equation. The relaxed mutual energy principle can add new boundary condition that radiation does not overflow the universe. This constitutes a new electromagnetic theory.