Based on the experimental data of differential cross sections of e-He elastic collisions at 2 eV, the e-He interaction potential has been drived theoretically by the inversion scattering method. Using the obtained potential, the differential cross sections of e-He elastic collissions at 2,5eV were calculated theoretically. The results show that: 1)The e-He interaction potential at extremely low-enery is real and local one and has the characters of strong Van der Waals potential. 2) The WKB inversion is fail for the present case, but the quantum inversion is still successful. 3) The quantum inversion potential can produecd good reaults in agreement with experimental data.