The invention relates to a device and a method for integrally processing garbage percolate, wherein the device comprises a denitrification mechanism, a polymerizing reaction tank, a sloping plate/pipe sedimentation tank, a biochar filter bed, an SMBR reactor and a medicine dissolving and dispensing mechanism, wherein the medicine dissolving and dispensing mechanism comprises three parallel medicine dissolving tanks including an alkali liquor tank, a flocculation liquid medicine tank and a flocculation aid liquid medicine tank; the three medicine dissolving tanks are respectively communicated with an alkali liquor medicine adding hole on a liquid inlet pipe of a stripping tower and a flocculation medicine adding hole and a flocculation aid medicine adding hole of pipelines communicated with a denitrification settling water tank and the polymerizing reaction tank. The treatment method comprises ammonia nitrogen stripping, coagulating sedimentation, biochar filter bed treatment, SMBR reactor treatment, nanofiltration and/or reverse osmosis treatment. The device and the method consist of a high-efficiency ammonia nitrogen stripping tower, whirl grid coagulation, sloping plate (pipe) setting, the biochar filter bed and the SMBR reactor, integrates the advantages of a garbage percolate treatment process and solves the problem of difficult treatment and high expense of the garbage percolate. The high-efficiency ammonia nitrogen stripping tower has high utilization rate on gases, a new gas distribution structure improves the energy efficiency, and the invention has the advantages of reducing the occupied area and reducing the operation expense.