The invention provides a radioactive waste oil electrochemical oxidation treatment device which comprises a liquid inlet tank, a liquid inlet pipe, an electrolytic tank and a liquid outlet pipe whichare sequentially communicated. An outlet end of the liquid outlet pipe is communicated with the liquid inlet tank to form a loop, the electrolytic tank comprises a tank body, a negative plate and a positive plate, an electrode in the electrolytic tank is connected onto a power supply through a lead, the negative plate and the positive plate in the electrolytic tank are parallel, and the distance between the positive plate and the negative plate is 1-3mm. As the distance between the positive plate and the negative plate is set within the range of 1-3mm, the reaction rate of electrochemical oxidation can be increased by the aid of cycle electrolysis, mass transfer between electrolyte and an electrode material is decreased, and organic matters in radioactive waste oil can be efficiently degraded.