A gear shifting assembly of a transmission, a transmission, and an automobile. The present disclosure aims to address the problem of complicated structure existing in a gear shifting assembly or the like. To this end, the gear shifting assembly of a transmission according to the present disclosure includes a P-gear mechanism and a forward-gear mechanism, wherein the gear shifting assembly further includes a drive mechanism and a shifting mechanism, and the shifting mechanism is configured to be capable of switching the drive mechanism so that the P-gear mechanism or the forward-gear mechanism is in an operational state. By employing the common drive mechanism, the gear-shifting function of forward gears and the function of parking at the P-gear can be realized without interference, and on the basis of function integration, elements are saved so that the gear shifting assembly is made more compact in structure.