The molecular models of tubular aluminumsilicate, imogolite, and tubular gibbsite for the comparison with imogolite were investigated by means of molecular dynamics simulations. The stability of these two models was tested in terms of the tube radii. It was shown that the total energy of tubular gibbsite is decreasing monotonically with the increasing radius of the tube. On the contrary, the total energy of imogolite has the minimum around diameter 2.6-2.9 nm. The details of the imogolite stability were inspected in terms of atom potential energy and the structural details.