<p>Can the glTF format be used for 3D printing?</p>

<p>If not, is there any tool can convert it to another format such as STL, OBJ, STEP, and IGES? </p>

As far as can be found it should be possible to convert glTF into STL (or OBJ).
You could try to use an online converter to do this, e.g.
this one (greentoken)
; and
this (assimp)
may be useful too.
According to
this
greentoken supports glTF as input and STL as output, but it is reported by @Trish that that does not work. Assimp could output STL files which then could be used by slicer programs to generate the specific G-code file to print the model on your printer.