The invention relates to a valve tappet device of an engine, which belongs to the technical field of mechanical structures. According to the technical scheme of the invention, the valve tappet device of the engine comprises a tappet body and is characterized in that a positioning groove is formed at the lower end of the tappet body, and concentric through holes which are vertical to the axial line of the tappet body are formed on two side wings forming the positioning groove; two ends of a roller pin are respectively positioned in the through holes of the two side wings; and a roller is arranged on the roller pin, and the roller is positioned in the positioning groove. The valve tappet device removes a bush between the roller and the roller pin, thereby reducing the number of parts, reducing the friction, reducing the cost and facilitating the production. The valve tappet device can increase the diameter and the width of the roller and the roller pin, improve the strength of the roller and the roller pin, reduce the contact stress between the roller and a cam, increase the reliability of a product, arrange an ejector rod slot on the tappet body, effectively increase the contact area between an ejector rod and the tappet body, significantly reduce the edge stress, greatly enhance the performances of abrasion resistance, tension resistance and pressure resistance and effectivelyprolong the service life of the tappet body.