Abstract: The molecular weight of two dextran standards imported from Sweden of known molecular weight and one batch of Chinese made dextran 70 were determined by low angle laser scattering photometer. The resulting values of the standards were in good agreement with the labelled values. The determined results of samples were high in precision(r=0.05). Calculated results of the least square method were approximately the same as those of the plotting method.LALLS conditions:Solvent: pure water (n_D²⁵=1.3314); filter: 0.22μm VG(Millipore Corp.); Annulus=6°～7°; field stop: 0.2; T=25℃.