Abstract: Paternal identification and constitution，reproductive fitness，pollen dispersal，genetic diversity levels and genetic distance in the semi-sibling families of a wild population of Paeonia lactiflora （Paeoniaceae），were analyzed based on AFLP markers. The pedigree between parental and seed populations was reconstructed，and gene flow，including its obstacles among pollen donors and acceptors within the population，was revealed. Nine pairs of selective AFLP primers amplified 255 clear bands，among which 113 were polymorphic. Analysis on the paternity of the semi-sibling families showed that selfing was as low as 2.25%，and total reproductive fitness with 95% confidence interval was 78.07%. The pollen dispersal showed a leptokurtic distances around a median of 5 meters（average 23 meters），reaching a farthest distance of 50 meters. The polymorphic ratio of parental population was 42.75%，the genetic diversity index，He，was 0.1683 ± 0.2083，and I was 0.2462 ± 0.2982；whereas P in seed population was 52.94%，He was 0.1921 ± 0.2055，and I was 0.2855 ± 0.2920. The range of genetic distances between the seeds（2.646–7.937）was slightly wider than that between the parental individuals（3.742–8.062）. The spatial genetic structure was visible only from 0 to 32 meters. The result showed that P. lactiflora is a strict out breeding species，but the distance of pollen dispersal was short，being influenced significantly by the geographic distances，which was accordance to neighbor dispersal model. The genetic diversity of the wild population was very low，and the genetic diversity level of the parental individuals was similar to that of the seeds. Merely in short distance the genetic structure was significant.

Key words: Paeonia lactiflora, paternity analysis, pollen dispersal, genetic structure