Metering performances in a pneumatic seeder of rapeseed processed with different pre-soaking methods, including pre soaking in warm water, cold water and without pre-soaking, were investigated to estimate whether sowing mechanization could be applied into the seeds qualified to agronomic requirement of pre-soaking. The results indicated that mechanical and physical properties of rapeseed had obvious change after soaking, which could be characterized by softened seed coat and increased 1000-grain weight and plumpness. Additionally, residual modulus degraded by 40%, the cracking load decreased by 10% and the cracking deformation aggrandized by 20%. When the rotational speed of seeder was slower than 36r/min, the sowing-performance as the quality of feed index for the three kinds of seed were more than 95%, while the miss index were less than 4%. Although the mechanical properties appeared degraded, the seeder never destructed the appearance and germinating ability of seeds. The results of the research concluded that rapeseed under pre-soaking would suitable for sowing mechanization with the pneumatic metering technology employed both positive and negative pressure.