Abstract: With the polysaccharides yield as target, the polysaccharides from pine needles of Pinus taeda L. was extracted and its antioxidant activity in vitro was determined. The ultrasonic-assisted extraction technology of polysaccharides from pine needles of P. taeda was confirmed by using Box-Behnken response surface methodology. The results showed that the optimal extraction process conditions were ultrasonic time 25 min, water extraction time 1 h, liquid-material ratio of 25:1(mL:g) and extraction temperature 91℃. Under optimal conditions, the yield of polysaccharides was up to 1.867%. The antioxidant activity in vitro was evaluated by measuring the DPPH·,·OH and ABTS+ free radical removal ability. As a result, the pine needle polysaccharides had a relatively strong capacity to scavenge DPPH,OH and ABTS+ free radical. They had a better concentration-response relationship. It showed that pine needle polysaccharides had an obvious antioxidant activity.