In order to obtain the optimal technical parameters for extracting Cathepsin L from Yak Meat,Plackett-Burman experiment was employed to screen the significant factors affecting the enzyme activity,which including pH of extraction buffer solution,L-Cys and ammonium sulfate saturation.The results of steepest ascent experiment,Central composite design and response surface analysis showed that the effects order from high to low of three factors on the enzyme activity were as follows: pH of extraction buffer solution,ammonium sulfate saturation and L-Cys.The optimal extraction process was pH5.68 of extraction buffer solution,6.48mmol/L L-Cys and 76.63% ammonium sulfate saturation.The enzyme activity of Cathepsin L reached 13.98Unit/mg under optimized conditions.The results showed the models fitted well the experimental data and the model was feasible,which provided a theoretical basis for further study on extraction technology for Cathepsin L from Yak Meat.