The invention discloses a highly-integrated multifunctional in-situ soil repairing complete apparatus. The apparatus comprises a main reaction tank and an integration device room which are connected by a pipeline, the main reaction tank comprises a dosing and reacting chamber, a Fenton oxidation chamber, a neutralization reaction chamber, a coagulation reaction chamber, an inclined plate sedimentation chamber, a sludge tank and a clear water tank which are sequentially connected, and an active carbon filter connected with the inclined plate sedimentation chamber and the clear water tank is arranged between the inclined plate sedimentation chamber and the clear water tank; and a self-cleaning filter, a sulfuric acid dosing device, a hydrogen peroxide dosing device, a ferrous sulfate dosingdevice, an alkali dosing device, a PAM dosing device and a volute sludge dewatering machine are arranged in the integration device room. The invention also discloses a water treatment method of the apparatus. The characteristics of an in-situ soil repairing technology and a Fenton oxidation technology are combined, and soil repairers are assembled to form the complete apparatus for production, sothe occupied area of the apparatus is reduced, and the integrated apparatus has complete functions; and two pipelines are connected, and devices are connected by steel wire flexible tubes, so the apparatus is easy to transport, mount and dismount.