The invention discloses a lever type online safety valve checking device. One end of a V-type lower rod and one end of the other V-type lower rod are hinged to each other, the two ends of a supporting rod adjusting nut are supported by one end of an upper rod and one end of each lower rod, a groove in a supporting rod upper bolt is hinged to one end of the upper rod, a tension sensor is arranged on the middle point of the upper rod, an iron chain and a clamping device with clamping heads provided with transverse tooth-shaped patterns are hung below the upper rod, a manual hydraulic pump is connected with a single-action hydraulic cylinder, the hydraulic cylinder is located on the open end of the lower rods through a hydraulic cylinder holding board, a hydraulic cylinder ejector rod is in contact with the upper rod, a displacement sensor is installed at the bottom of the hydraulic cylinder, a safety valve body is arranged in protruding V shapes of two pressing rods, and a valve neck of a safety valve is clamped by a locking device; the clamping device can clamp a valve rod of the safety valve, the valve rod of the safety valve and the tension sensor are coaxially arranged, and the displacement sensor and the tension sensor are connected with a data processor through data cables. According to the lever type online safety valve adjusting device, the valve rod is lifted according to the lever principle, the power and the size of a lifting mechanism are effectively reduced, checking is rapid and accurate, the application range is wide, and the checking efficiency can be effectively improved.