The invention discloses a hook sash cover plate sectional bar of a thermal-insulation sliding window and relates to the field of building materials. The hook sash cover plate sectional bar comprises a hook sash assembly and a hook sash cover plate, wherein the hook sash assembly is composed of an inner parted body, an outer parted body and a connecting part connecting the inner parted body and the outer parted body, thermal-insulating glass is fixed to the left end of the hook sash assembly, the hook sash cover plate is assembled at the right end of the hook sash assembly, a plastic clamping part is arranged between the inner parted body of the hook sash assembly and the hook sash cover plate, the plastic clamping part is bent to be in the shape of U, and the right end of the inner parted body is sleeved with the plastic clamping part. The hook sash cover plate sectional bar is simple in structure, reasonable in design, convenient to construct and install, safe and environmentally friendly in use, high in production efficiency, low in cost, good in sealing performance, low in noise and capable of being widely applied to alloy sliding sashes, and components can not deform easily.