In order to solve the problem of small seed's precision seeding such as rapeseed seeds and complex structure caused by traditional metering device's multiline sowing, a pneumatic centralized metering device was developed. The structure and parameters were analyzed. With “Chinese hybrid 4” rapeseed as the test object, seeding consistency test and seeding uniformity test were applied to research the vacuum value and rotate speed of the roller that influenced the sowingperformance mainly. According to experiment analysis, the influencing regularity and the optimization of all the factors were defined. The analyses of the experiment results indicated that the vacuum value was the most important factor, the second was rotate speed. The optimum operation condition were: vacuum value of -1.5kPa and rotate speed of the roller of 20r/min. 