The utility model relates to the technical field of test equipment. The utility model relates to a viscometer, in particular to a silicon mortar viscometer. The device comprises a base, a column, a control box, a rotating shaft and rotors. The stand column is vertically arranged on the upper surface of the base. The control box is arranged on one side of the stand column. The control box is located over the base. The rotating shaft is of a hollow structure and is vertically arranged below the control box; the rotor is coaxially and vertically arranged below the rotating shaft; a connecting shaft is arranged at the upper end of the rotor; an inserting assembly is arranged on the peripheral surface of the connecting shaft; the inserting assembly comprises an elastic piece and a rotating plate; the rotating plate is hinged with the peripheral surface of the connecting shaft; a hinge shaft of the rotating plate and the connecting shaft is arranged on the upper end surface of the rotating plate; the elastic piece is arranged on the lower side of the rotating plate and fixedly connected with the connecting shaft, a clamping groove matched with the rotating plate is formed in the rotatingshaft, when the rotating plate is clamped in the clamping groove, a gap exists between the upper end face of the connecting shaft and the upper end face of the rotating shaft, and the effects that the rotor is convenient to replace and the measurement accuracy is improved are achieved.