Abstract: The photosynthetic characteristics and Cd accumulating capacities of two Helianthus tuberosus varieties (NY5, NY2) at different Cd concentrations (0, 5, 25, 50, 100, and 200 mg/L), were investigated for the potential use of H. tuberosus as a candidate for phytoremediation of Cd-contaminated soils. 1) The biomass of NY5 and NY2 were significantly reduced by Cd stress, but the reduction was less for NY5 than for NY2. 2) The chlorophyll content of NY5 was lowest in the 100 mg/L Cd treatment, while for NY2, the lowest value was observed in the 25 mg/L Cd treatment. The carotenoids content of NY5 under Cd stress was higher than that of the control, while the opposite was observed for NY2. 3) With the increase in Cd concentration, net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) significantly decreased, but the intercellular CO₂ concentration (Ci) was relatively stable. Water use efficiency (WUE) and stomatal limitation (Ls) of NY5 showed similar change trend under Cd stress with the lowest value observed at 50 mg/L Cd, while for NY2, there was little change. 4) NY5 and NY2 had Cd tolerance and accumulation capacity at high concentrations of Cd stress, but the capacity of NY5 was greater than that of NY2. H. tuberosus may therefore be an excellent candidate for phytoremediation on Cd-contaminated soils, and NY5 may be better than NY2.