  The ALICE Collaboration aims at studying the physics of strongly interacting
matter by building up a dedicated heavy-ion detector. The Inner Tracking System
(ITS) is located in the heart of the ALICE Detector surrounding the interaction
point. Now, ALICE has a plan to upgrade the inner tracking system for rare
probes at low transverse momentum. The new ITS composes of seven layers of
silicon pixel sensor on the supporting structure. One goal of the new design is
to reduce the material budget ($X/X_0$) per layer to 0.3$\%$ for inner layers
and 0.8$\%$ for middle and outer layers. In this work, we perform the
calculations based on detailed geometry descriptions of different supporting
structures for inner and outer barrel using ALIROOT. Our results show that it
is possible to reduce the material budget of the inner and outer barrel to the
value that we have expected. The manufacturing of such prototypes are also
possible.
