The method of quadratic regression general rotation was used to optimize the parameters of seed cotton cleaning apparatus .The results showed that the main factors of impacting impurity rate walking were the barbed nails drum speed, serrated roller speed and cotton brush roller speed. The three factors gradation importance was the serrated roller speed, cotton brush roller speed and barbed nails drum speed. Optimal group of parameters was the serrated roller speed of 291r/min, the cotton brush roller speed of 695r/min,the barbed nails drum speed of 367r/min. In this case, the impurity was 15.10%.