The invention provides a high-concentration waste water pretreatment device. The device comprises a water storage pond used for storing to-be-treated waste water, a three-dimensional electrode electrochemical reactor used for conducting electrochemical oxidation, catalytic oxidation and adsorption treatment on the waste water and decomposing and adsorbing organic matter pollution in the waste water, and a mud discharge device used for discharge mud generated by the waste water subjected to electrochemical oxidation, catalytic oxidation and adsorption treatment. The three-dimensional electrode electrochemical reactor comprises an electrolytic tank, a pair of solid state electrodes installed in the electrolytic tank, and particle electrodes located in the electrolytic tank. The high-concentration waste water pretreatment device has a very good processing effect on high-concentration organic waste water difficult to decompose. After treatment achieved through the device, the concentration of COD in high-concentration organic waste water with the concentration being thousands to tens of thousands mg/L can be reduced to 10000 mg/L or below, and basic conditions for the waste water entering an anaerobic and aerobic biochemical treatment system are met.