environmental protection printing has no damage to human body fig2 is a structural schematic view of an electronic cigarette of a second embodiment of the present application in fig2 there is at least one containing grooves 10 used for containing the first paint layer 2 forming on the outer wall of the outer sleeve 1 the containing grooves 10 extend axially along the outer wall of the outer sleeve 1 and are circumferential grooves unlabeled the grooves extend to two ends of the outer sleeve 1 namely the outer wall of the outer sleeve 1 is completely covered with the grooves the first paint layer 2 is arranged in the grooves fig3 is a structural schematic view of an electronic cigarette of a third embodiment of the present application in fig3 the first paint layer 2 can only covers part of the outer wall of the outer sleeve 1 in this embodiment the containing grooves 10 can be multiple grooves configured separately axially along the outer wall of the outer sleeve 1 the first paint layer 2 are respectively contained in each groove fig4 is a structural schematic view of an electronic cigarette of a fourth embodiment of the present application in fig4 the containing grooves 10 can be multiple grooves configured separately radially along the outer wall of the outer sleeve 1 the first paint layer 2 is respectively contained in each groove advantageously in the above embodiments a thickness of the first paint layer 2 is the same as a depth of the containing grooves 10 further the thickness of the first paint layer 2 ranges.