  Backward elastic $p ^3He$-scattering at incident proton kinetic energies
$T_p>1$ GeV is investigated in the framework of the np-pair transfer mechanism
and triangular diagram of one-pion exchange with a subprocess $pd\to ^3He\pi^0$
using a realistic three-body wave function of the $^3He$ nucleus.
  It is found that the $np-$pair transfer mechanism dominates owing to a rich
high momentum component of the $^3He$ wave function.
  We show that the experimental cross section of this process is defined mainly
by the values of the Faddeev component of the $^3He$ wave function, $\phi
^{23}({\bf q}_{23}, {\bf p}_1)$, at high relative momenta $q_{23}> 0.6 GeV/c$
of the NN-pair in the $^1S_0$-state and at low spectator momenta $p_1\leq 0.1$
GeV/c. The spin-spin correlation parameter is calculated in the framework of
the dominating mechanism for the case of polarized target and beam.
Rescatterings in the initial and final states are taken into account.
Comparison with the $pd\to dp$ process is performed.
