The utility model discloses a device for measuring the water content of materials by a microwave combination weighing technology, which belongs to the technical field of measuring instruments, and comprises a microwave transmitting antenna (1), a bearing platform (3), a weighing sensor (4), a computer (8) and the like; the positions of the microwave transmitting antenna (1) and a microwave receiving antenna (2) are opposite to each other, and the weighing sensor (4) and the bearing platform (3) are arranged between the microwave transmitting antenna (1) and the microwave receiving antenna (2); and a microwave network (5) and the weighing sensor (4) are respectively connected with an electronic signal processing circuit (7) which is connected with the computer. A sample bucket is placed on the bearing platform, a microwave source emits microwave, the microwave enters the receiving antenna after penetrating the coal by the transmitting antenna, the microwave network and the electronic signal processing circuit process and record the attenuation and phase information of the microwave after penetrating the coal, and the water content of the coal is calculated. The utility model has simple operation, is rapid and accurate, can reduce the influences of the sample stacking density, granularity, uniformity and other factors on the measuring accuracy, and has wide applicability.