We calculated the structure factor of a semidilute polymer solution under continuous shear flow using a theory first proposed by Helfand and Fredrickson which describes the dynamical coupling between stress and diffusion based on a two-fluid model. The Kaye-BKZ constitutive equation is applied to the stress term in the theory in order to express the non-Newtonian behavior, the normal stress effect, and the distribution of the stress relaxation. By taking account of the distribution of the stress relaxation, we can calculate the structure factor, in the context of a linearized dynamical equation, in the high shear rate regime (gamma) over dot tau (m) > I with tau (m) being the maximum relaxation time, at which the comparison between the theory and the experimental results is of greatest interest. Although the resulting structure factors show a qualitative agreement with experiments, some discrepancies exist such as the (gamma) over dot dependence of the peak position. We also examine the effect of normal stress on the structure factor and the value of (gamma) over dot at which the intensity diverges. The theoretical results are discussed in conjunction with experimental findings.