The invention discloses a vehicle-mounted full hydraulic multifunctional deep well drilling machine, comprising an all-axle driven automobile chassis, wherein the tail part of the automobile chassis is provided with a drilling mechanism; the drilling mechanism includes a mast; a power unit, a winding device, a shackle device and a porthole device are installed on the mast; a hydraulic power station of the drilling machine is installed on the automobile chassis; hydraulic legs are installed at four corners of he automobile chassis and the bottom of the mast; the mast includes a fixed mast part and a movable mast part; the porthole device is arranged at the lower part of the fixed mast part; a feeding cylinder, the movable mast part, a steel wire rope I and a steel wire rope II form a multiplication mechanism; and the feeding manner is characterized in that the stroke of the power unit is twice more than that of the piston of the feeding cylinder. The vehicle-mounted full hydraulic multifunctional deep well drilling machine has the advantages of good maneuverability, high degree of integration, short preparation time, high work efficiency and good adaptability for strata, satisfies requirements for coal mine rescue drilling, and also can be applied to drilling holes with different diameters, such as coal seam gas extraction holes, shallow oil and gas wells, geothermal wells, water wells and the like.