The invention discloses a multifunctional maintenance service device for a petrol drilling machine. The whole device comprises an installation frame, a swing support, a working arm, a working basket, various hydraulic oil cylinders, an operation platform and the like, wherein the operation platform is used for realizing the lifting, swinging, stretching and retracting functions of the working arm and placing the working basket at the positions of casing operation and maintenance service operation. By the multifunctional maintenance service device for the petrol drilling machine, case straightening equipment of the petrol drilling machine can be safely lifted and accurately positioned at an optional position in a derrick on the premise of meeting the requirement of case straightening during drilling operation, so that working staff can conveniently maintain and serve a top driving device and other equipment, and the like.