Abstract: A high resolution study of the high-n Rydberg H atom scattering with helium was carried out using the H atom Rydberg tagging time-of-flight technique. Differential cross sections were measured for scattering process of H(n)+He→H(n′)+He at the collision energy of 0.526 eV. Experimental result indicates that the scattered H(n′) product is mainly forward distributed, with signals observed in the wide range of angles at the sideway and forward scattering directions. At the sideway and forward directions, a lot of oscillatory structures in the angular distributions are present. Detailed analysis also shows that the principle quantum number, n, is not changed much for the Rydberg H atom at the forward scattering direction. This work provides a good test ground to investigate theoretically the exact collision dynamics between the high-n Rydberg H atom and the helium atom.