The invention discloses a dotting mechanism of a fingerprint module. The mechanism comprises a base. A translation mechanism is arranged on the base. A dotting assembly is arranged on the translationmechanism. The translation mechanism comprises a sliding rail, a sliding block slidably connected with the sliding rail, and a motor for driving the sliding block to move along the sliding rail. The dotting assembly comprises a support, multiple cylinder installation racks, multiple cylinders, multiple clamping pieces and multiple marking pen heads. The support is installed on the sliding block. The cylinder installation racks are parallelly arranged on the end part of the support. The cylinders are vertically installed on the cylinder installation racks. Telescopic rods of the cylinders are downwards. The clamping pieces are installed on the telescopic rods of the cylinders and are used for clamping the marking pen heads. Each clamping piece comprises a rectangular block body. A pen headinsertion hole is arranged near the end part of each rectangular block body. Internally recessed openings extending to the insertion holes of the pen heads are arranged in the end parts. Opposite boltholes are arranged in two side walls of each opening. The marking pen heads are inserted into the pen head insertion holes. A blocking column for blocking the support is arranged on the end part of the sliding rail.