Overshoot of shear stress, sigma, and the first normal stress difference, N-1, in shear flow was investigated for dilute solutions of polystyrene with very high molecular weight in concentrated solution of low M PS. In the case that the matrix was a nonentangled system, behavior of overshoot was similar to that of dilute solution of high M PS in pure solvent. The magnitudes of shear, gamma(sigma m) and gamma(Nm), corresponding to the peaks of sigma and N-1 lay on the universal functions of (gamma) over dot tau(R), respectively, proposed for dilute solutions in pure solvent. Here tau(R) is the Rouse relaxation time for high M PS in the blend evaluated from dynamic modulus at high frequencies. In the case that the matrix was an entangled system, an additional a peak was observed at high rates of shear at times corresponding to gamma(sigma m) = 2-3. This peak can be assigned to the motion of low M chains in entanglement network. When the matrix was entangled, stress overshoot was observed even at relatively low rates of shear, say (gamma) over dot tau(R) < 10(-2). This is probably due to the motion of high M chains in entanglement of all the chains. In this case the gamma(sigma m) and gamma(Nm) values were higher than those expected for entangled chains of monodisperse polymer in pure solvent.