Abstract:Fingerprinting of three very early Brassica napus restorer lines by using SSR molecular markers . CO dominant SSR markers were found in the 3 early maturing B.napus restorer lines and their F1; Those primers were used to determine the outcrossing rate of these 3 restorer lines in fields. The results showed that the outcrossing rate of these restorer lines (4395, 3509, 4152 ) were respectively in 46.02%, 33.32%, 18.12%, there was a significant difference in p = 0.01, it illustrated that the outcrossing rate of three very early maturing B.napus restorer lines had differences; And It provided a basis that to determine the proportion of three very early Brassica napus restorer lines in Synthetic hybrids.