The invention relates to a radioactive organic waste liquid solidification device and method. The device comprises a motor, a bracket, a stirring shaft, a stirring paddle, a solidification kettle, a fixing frame and a discharging valve. The method comprises the following steps: 1, adding a certain amount of radioactive organic waste liquid into a solidification kettle at room temperature; and 2, under the condition of continuous mechanical stirring, adding a thickening agent, wherein the stirring speed is 45-55 rpm, the stirring time is 45-60 min, and the organic waste liquid becomes dark in color, is not clear any more, but still has good fluidity. According to the invention, the problem of radioactive organic waste liquid solidification is solved, and the device has the advantages of compact structure, stable operation, convenient operation, good product solidification effect and the like.