The acceleration of the polarized protons at RHIC will open a new era of the high energy spin physics. Among a wealth of spin physics capability, expected sensitivities for the spin structure of the nucleon are presented.
The gluon helicity distribution will be measured via high-
prompt photon productions. A typical error of the measurement will
be 3-40% at 0.1<x<0.3 in pp collisions at 
GeV, and
1-8% at 0.05<x<0.1 in pp collisions at 
GeV.
Optional check with heavy quark production will be helpful
for further studies.
The anti-quark helicity distribution will be extracted from the asymmetry for W production. The production will also provide tool for flavor decomposition of anti-quark helicity, as well as the quark helicity distributions.
Figure 6: Expected sensitivities for the flavor decomposed
asymmetry in the structure functions imposed on the model predictions
by Bourrely and Soffer [24] and by Gehrmann and Stirling
[25] (GS95LO(A)).