The total differential cross section, elastic differential cross section and inelastic differential cross section for collision between He isotopic atoms and NO molecule have been calculated by using close-coupling approximation method. The influence of He isotope on the differential cross section for He-NO collision system has been given. The calculated result shows that the total differential cross section at 0 degree increases, and rainbow phenomenon of collision of He isotopic atoms with NO molecule is more evident along with increase of incident He isotope mass at identical incident energy. At the same time, the effect of increased reduced mass is larger than the effect of diminished relative velocity of collision between He atom and NO molecule, and enables the scattering spacing of the oscillation to gradually decrease.