To initially investigate the antioxidant capacity in vitro of crude polysaccharides from Cistanche(Cistanche deserticola and C. tubulosa) and its adulterants (C. salsa,C. sinensis,C. lanzhouensis and Orobanche cernua),their ability of crude polysaccharides to scavenge DPPH·,·OH,and ABTS· and their total antioxidant capacity (T-AOC) were determined respectively.Simultaneously,the Topsis method was used to comprehensively analyze the antioxidant capacity in vitro of those crude polysaccharides from six medicinal plants.As a result,the order of antioxidant capacity in vitro of their crude polysaccharides was as follows:C. tubulosa> O. cernua> C. deserticola> C. lanzhouensis> C. sinensis> C. salsa.Among them,the antioxidant capacity in vitro of crude polysaccharides from O. cernua and C. lanzhouensis is close to authentic Cistanche.This study comprehensively evaluated the antioxidant capacity in vitro of crude polysaccharides from six medicinal plants of Cistanche and its adulterants,which can provide a significant reference for the comprehensive development of related medicinal plant resources such as Cistanche and its adulterants.