The processing technology of a molybdenum-niobium alloy plate target shall be implemented as follows: (1) mix: divide a certain amount of molybdenum powder and niobium powder into, at least, three small portions, and mix each portion of them into a mixed powder. After several rounds of mixing and sieving, a mixed alloy powder will be achieved from a plurality of mixed powders; divide the mixed alloy powder into three portions and mix each portion with other materials, a uniform alloy powder will be obtained by mixing the three portions together; (2) shaping: the alloy compact, which is formed after isostatic pressing, shall be sintered in a high-temperature intermediate frequency furnace for at least 3 hours under protection of hydrogen. The sintering temperature includes three zones, i.e. 0° C.˜800° C., 800° C.˜1600° C. and 1600° C.˜2000° C., and the alloy compact shall be sintered in each of the three temperature zones. An alloy compact shape will be formed in the end; (3) forging and rolling: after the forging and densification under a temperature of 1200° C.˜100° C., the alloy compact is rolled into the plate for material preparation under a heating temperature of 1500° C.˜1600° C.; (4) finish machining: the final molybdenum-niobium alloy plate target is achieved by cutting, accurate grinding and machining. The blank of the invention is the refined grain with a relatively uniform size.