Openable device for rear window glass of pickup truck

The invention provides an openable device for rear window glass of a pickup truck. The openable device comprises right half glass, left half glass, a right guide rail, a left guide rail, a right guidewheel, a left guide wheel and a locking mechanism, wherein the right guide rail and the left guide rail are crossed to form an X-shaped guide rail, the depths of slideways of the right guide rail andthe left guide rail are different, and the X-shaped guide rail is arranged on the upper end face and the lower end face of a rear window glass frame of the pickup truck. The right guide wheel and theleft guide wheel are fixed to the upper end face and the lower end face of the right half glass and the left half glass through a right guide wheel shaft and a left guide wheel shaft respectively, the height sum of the right guide wheel and the right guide wheel shaft is equal to the slideway depth of the right guide rail, and the height sum of the left guide wheel and the left guide wheel shaftis equal to the slideway dep