Abstract: Objective Choose a microsatellite loci with better polymorphism to analyse DNA polymorphism of 6 strains of rat with a view to establishing a reliable and accurate, efficient and feasible genetic monitoring method. Method Fifteen rat microsatellite loci on different chromosomes were used to analyse the microsatellite DNA polymorphism among 6 rat strains by PCR methods. Result The nine microsatellites DNA could be amplified efficiently and displayed polymorphism among the various strains and no polymorphism in the same rat strains. Conclusion With the continuous deepening study of microsatellite DNA polymorphism of rat, the microsatellite DNA markers can replace the biochemical analysis，and be widely used in genetic monitoring.

Key words: Rat, Micro satellite DNA, Genetic monitoring