Abstract: The antioxidantive activity of polymers proanidins depolymerization product of Pinus yunnanensis was studied by analyzing the POV value, reductive ability, the clearance rate of DPPH and hydroxyl free radical. The results showed that the antioxidantive activity of polymers proanidins depolymerization product of P. yunnanensis was obvious, whose IC50 was 2.32 mg/mL for DPPH· and 154 mg/mL for ·OH, while the IC50 value of BHT was 300 mg/mL for DPPH and 1.81mg/mL for ·OH respectively, indicating that the DPPH· and ·OH elimination capability and the reductive ability of the depolymerization product from polymer proanidins of P. yunnanensis was similar to that of BHT. The study showed there was a relationship between the DPPH· and ·OH elimination capability and the sample concentration.