The invention discloses a treatment device for zinc-containing casting wastewater, relating to the technical field of wastewater treatment. The treatment device comprises a collecting-filtering tank,an electrolytic reaction tank, a pH adjusting tank, a coagulative precipitation tank, an adsorption tank and a disinfection tank, wherein an electrolytic system is arranged in the electrolytic reaction tank and comprises a direct current power supply, an anode wiring terminal of the direct current power supply is connected with an anode plate through a power supply lead, a negative wiring terminalof the direct current power supply is connected with a cathode plate through a power supply lead, and the anode plate and the cathode plate stretch into the electrolytic reaction tank; a pH sensor and a pH adjusting reagent tank are arranged in the pH adjusting tank, and a liquid adding pipe is arranged on the pH adjusting regent tank; and a mud discharging hole is formed in the lower end of thecoagulative precipitation tank; and haycite is placed in the adsorption tank. The invention further discloses a treatment method for the zinc-containing casting wastewater. According to the device andthe method, the removal rate of zinc in the casting wastewater reaches 99%, and the quality of the treated water is accordant with the emission standard.