In a recent paper, the form factor of radiation scattering in a bi-maxwellian plasma had been calculated, distinguishing the case T⊥≥T∥ form the case T⊥≤T∥ . It had led to different analytic expressions for the form factor in these two cases respectively. The present note shows that it is not necessary to differentiate the cases T⊥≥T∥ and T⊥≤T∥, and the common analytic expression for the form factor can be obtained with better accuracy.