Rice protein powder was used as raw material to prepare rice oligopeptides by two-step enzymatic hydrolysis. The effects of different temperatures， pH values and digestion modes on the structure and antioxidant activity of rice oligopeptides were studied with the molecular weight distribution， secondary structure and oxygen radical absorbance capacity (ORAC) as indicators. The results showed that heat treatment significantly reduced the molecular weight of rice oligopeptides in the range of 2 000-3 000 u， 3 000-5 000 u and above 5 000 u(P＜0.05)， significantly increased the molecular weight of rice oligopeptides in the range of below 150 u (P＜0.05)， but had no significant effect on the weight average molecular weight and secondary structure(P＜0.05). The ORAC value of rice oligopeptides at 40 ℃ was significantly higher than that at other temperatures (P＜0.05). The pH value had no significant effect on the weight average molecular weight， α-helix and parallel β-pleated sheet of rice oligopeptides (P＞0.05). ORAC value of rice oligopeptides at pH 6 was significantly higher than that of the control group (P＞0.05)， while ORAC values of pH 2 and pH 4 were significantly lower (P＜0.05). Simulated digestion in vitro significantly reduced the molecular weight of rice oligopeptides in the range of 1 000-2 000 u， 2 000-3 000 u， 3 000-5 000 u， above 5 000 u and the weight average molecular weight (P＞0.05)， but the proportion of less than 150 u was significantly increased (P＜0.05)， but the secondary structure had no significant change (P＞0.05). The ORAC value of rice oligopeptides were significantly increased by pepsin digestion plus further trypsin digestion (P＜0.05). The above research results show that rice oligopeptides have certain structural stability and antioxidant activity， which lays a theoretical foundation for the development of antioxidant functional beverages.