  The proton spin crisis remains an unsolved problem in particle physics. The
spin and angular momentum of the partons inside the proton are non-perturbative
quantities in QCD which cannot be calculated by using the perturbative QCD
(pQCD). In this paper we present the lattice QCD formulation to study the
proton spin crisis. We derive the non-perturbative formula of the spin and
angular momentum of the partons inside the proton from the first principle in
QCD which can be calculated by using the lattice QCD method.
