Tartary buckwheat protein hydrolysate was prepared with tartary buckwheat protein as substrate, hydrolyzed by Alcalase 2.4 L, papain, pepsin, trypsin, and combination of pepsin and trypsin to simulate in vitro digestion. The antioxidant properties of different protein hydrolysates were tested by DPPH and ABTS+·scavenging ability. The result showed that the order of the degree of hydrolysis of different proteases hydrolysates was: Alcalase 2.4 L > pepsin+trypsin >pepsin> papain>trypsin. The tartary buckwheat protein hydrolysate by Alacalase 2.4 L had highest degree of hydrolysis of 29.95%. The original tartary buckwheat had antioxidant ability. The highest scavenging ability of DPPH and ABTS+·of original tartary buckwheat protein was 71.91% and 11.25%, but both of them were significantly lower than positive control group of Vc. With the increase of hydrolysis degree, the antioxidant ability of protein hydrolysate increased. The protein hydrolysates from Alcalase 2.4 L showed the highest antioxidant ability, which was significantly higher than original tartary buckwheat protein. The highest scavenging ability of DPPH and ABTS+·of protein hydrolysates from Alcalase 2.4 L were 91.65% (0.5 mg/mL) and 16.67% (1 mg/mL), respectively. At high concentration (>0.5 mg/mL), protein hydrolysates from Alcalase 2.4 L showed no significant difference compared with positive control of Vc. Besides, protein hydrolysates from Alcalase 2.4 L showed significantly higher antioxidant properties than other protein hydrolysates. Therefore, the tartary buckwheat protein hydrolysate by Alcalase 2.4 L could be used as an antioxidant.