Up to now, 11 arsenic hyperaccumulators and 4 non-hyperaccumulators in Pteris genus have been reported. The non-hyperaccumulators could be used as controls to reveal the responsive mechanisms of hyperaccumulators to arsenic pollution. Auxin plays an important role in plant cell growth, differentiation and division. In the present research, one arsenic hyperaccumulator (Pteris cretica var. nervosa)and one non-hyperaccumulator (Pteris ensiformis) were selected from Pteris genus to evaluate the effects of arsenic stress (0, 50, 100 and 200 mg/kg) on the plant biomass, height, frond indole-3-acetic acid (IAA) contents, arsenic accumulation, the activities of IAA oxidase and antioxidative enzymes (superoxide dismutase SOD, peroxidase POD and catalase CAT), as well as the content of malondialdehyde (MDA, a per-oxidation product of cell membrane lipid) using a pot experiment. The relationship among the contents of IAA, arsenic concentration, activities of 3 antioxidative enzymes and MDA contents in the fronds of two plants were also analyzed by step regression statistical method. In addition, the variation of IAA, IAAO, SOD, POD, CAT and MDA in two plants exposed to 100 mg/kg arsenic with culture time was examined. No significant difference was observed in the biomass and height of P. cretica var. nervosa under arsenic stress compared to the control (0 mg/kg), but a significant decrease was noted in P. ensiformis under medium or high arsenic stress. The concentrations of arsenic and IAA increased but the activity of IAAO decreased in the fronds of two plants exposed to medium or high arsenic stress, but this change was more significant in P. cretica var. nervosa. The activities of 3 antioxidative enzymes could maintain or increase in the fronds of P. cretica var. nervosa exposed to arsenic stress, but a significant decrease of POD was observed in P. ensiformis, in which the activities of SOD and CAT could maintain. Therefore, much stronger antioxidative ability was shown in P. cretica var. nervosa exposed to arsenic stress. The results from step regression analysis showed a significantly positive correlation between the IAA contents and arsenic concentrations in the fronds of two plants, and a significantly negative correlation was also observed between the IAA contents and CAT activities in the fronds of P. cretica var. nervosa. The result from time-course effect research showed that the highest IAA contents, the lowest IAAO and CAT activity were found in the 13th days in the culture process of P. cretica var. nervosa exposed to 100 mg/kg, but similar result was not observed for P. ensiformis. Therefore, a higher IAA contents, a lower IAAO and CAT activities may have contributed to arsenic hyperaccumulation in P. cretica var. nervosa.