The invention discloses a foam ring and gear assembling machine, comprising a rack, wherein the rack is provided with a conveying group for conveying gears, a foam ring feeding group for conveying foam rings, and a manipulator; the rack is provided with an intercepting assembly capable of intercepting the gears from the feeding group and limiting the gears; and the manipulator can punch out foam cores of the foam rings, and transfer the foam rings with the foam cores punched out and sleeve the gears intercepted by the intercepting assembly with the foam rings with the foam cores punched out. The foam ring and gear assembling machine utilizes the interception assembly to intercept the gears from the conveying group and position the gears at the same time, so that the installation is convenient and accurate; the manipulator can be used for punching out foam cores from the foam rings conveyed by the foam ring feeding group, then, the manipulator cooperates with the intercepting assembly for sleeving rotating shafts of the gears with the foam rings with the foam cores punched out, so that the manipulator can simultaneously have the function of punching out and carrying and assembling and can simultaneously punch the foam cores and assembling the foam rings on the gears, thereby greatly improving the assembly efficiency of the gears and the foam rings, and simultaneously reducing the labor cost and the labor intensity.