Structures of Newtonian super-massive stars are calculated with the opacity for Compton effect K 0/(1 + αT), where k 0 = 0.2(1 + X) and α = 2.2 × 10−9 K−1. The track of the Main-Sequence is turned right in the upper part of the HR diagram. Mass loss will occur in a Main-Sequence stage for a star with mass larger than a critical mass. The cause of mass loss and the expansion of the radius is continuum radiation pressure. The critical mass for mass loss is 1.02 × 106 M ⊙for a Population I star, and 1.23 × 105 M ⊙ for Population III star. Mass loss rates expected in these stars are 3.3 x 10−3 and 4.0 × 10 −3 M ⊙ yr−1, respectively.