The invention discloses a connecting rod mechanism applied to an engine, which comprises a first spherical hinge connecting rod seat, a second spherical hinge connecting rod seat, a spherical hinge connecting rod and a seat rod; the spherical hinge connecting rod comprises a columnar rod body, and a first spherical hinge joint and a second spherical hinge joint which are respectively arranged on both ends of the rod body and are in spherical shapes, and an I-shaped channel is arranged in the spherical hinge connecting rod; the first spherical hinge connecting rod seat is correspondingly matched and hinged with the first spherical hinge joint, and is arranged in the installation cavity of the seat rod; and the second spherical hinge connecting rod seat is correspondingly matched and hinged with the second spherical hinge joint. The connecting rod mechanism applied to the engine has the advantages of strong load capability, uniform stress, high working efficiency, simple structure, low manufacturing cost and long service life.