Abstract: Taking PPC of Pinus yunnanensis bark as material, the content of fragmented product 1 was the evaluation index. The effects of reaction temperature, reaction time, concentration of hydrochloric acid and PPC/TP on the formation of fragmented proanthocyanidins from P.yunnanensis bark were analyzed by single factor experiments. Response surface method was used to optimize the reaction conditions, the main product content as a response value, the survey data of 30 test points were subjected to multivariate nonlinear analysis, and a significant test of regression model was conducted by ANOVA. The results showed that the best fragmentation conditions were reaction temperature 51 ℃, reaction time 120 min, HCl concentration 3% and PPC/TP ratio=1:1. Under these conditions, the actual content of the product reached 861.897 μg/mL that well matched with the predicted values (864.664 μg/mL), indicated it was feasible that the response surface method to optimize the fragmentation process of PPC from P.yunnanensis barks.