The invention relates to a device and a method for using microwaves for removing tumors, stopping bleeding, clotting, relieving pains and improving blood circulation. The method includes: using a camera 28 for shooting a lesion 4, enabling a computer 32 to control a scribing machine 31 to scribe voids 13, 14 and 15 of metal stencils 8, 9 and 10 of a three-dimensional lesion projection, radiating microwave beams 19, 20 and 21 penetrating the voids of the stencils in turns from an opposite three-dimensional direction of the projection direction onto the lesion, and enabling the microwave beams to form a high-temperature microwave radiation area 26 coincident with the three-dimensional projection, wherein the temperature of the high-temperature microwave radiation area 26 is higher than a withstanding temperature 43 DEG C of cancer cells; enabling a normal cell tissue 53 to be positioned in a temperature area 25 formed by radiation of nonoverlapped one-dimensional wave beams, wherein the temperature of the temperature area 25 is lower than 40 DEG C. The metal stencils define radiation ranges and positions, a pulse microwave generator and a lens antenna transmit parallel microwave beams 44, 45 and 46, running water controls radiation sequence, and a pyroelectric infrared thermometer and an overtemperature power cut circuit control the radiation temperature. Accurate heating position and range, safety in treatment, painlessness, quickness, one-time completion and thoroughness in killing of cancer cells and low cost are realized.