The invention discloses a mercury-containing sewage and a mercury-containing sludge treatment method. The method is implemented with a buffer tank, a horizontal slop oil tank, an oxidation tank, sewage pumps, a capture coagulation tank, a jet air flotation device, an adsorption tower, a double filter material filter, a backwash water tank, a sludge collection tank, a sludge concentration tank, a mixing tank, a horizontal screw centrifugal dewatering device, an automatic sludge packaging machine, a coalescer and a gas mercury removal adsorption tower, wherein the buffer tank, the oxidation tank, the sewage pump, the capture coagulation tank, the sewage pump, the jet air flotation device, the sewage pump, the adsorption tower and the double filter material filter are sequentially connected with each other, and the buffer tank, the oxidation tank, the capture coagulation tank and the jet air flotation device are connected to the upper side of the sludge concentration tank and also connected to the lower ends of the coalescer and the gas mercury removal adsorption tower, respectively. The treatment method comprehensively considers oil-water separation, mercury oxidation, mercury capture flocculation, mercury adsorption filtration, stabilization of mercury in sludge and sludge drying packaging, realizes integrated treatment of mercury-containing sewage and mercury-containing sludge,and provides technical reference for treatment of mercury-containing sewage and sludge of gas fields.