The temperature dependence of the 195Pt Knight shift, K, for the high quality single crystal UPt3 has been measured down to T = 28 mK in applied magnetic fields parallel and perpendicular to the hexagonal c axis. No change of K's has been found across the superconducting transition temperature Tc down to 28 mK regardless of the crystal directions and independent of the superconducting multiphases. It is demonstrated that UPt3 is the odd-parity superconductor with parallel spin pairing following the direction of the magnetic field in a range of 4.4–15.6 kOe without an appreciable pinning of the order parameter to the lattice.