Abstract: Fourteen restriction endonucleases,ApaⅠ,AvaⅠ,BamHⅠ,BglⅠ,BglⅡ,DraⅠ,EcoRⅠ,EcoRⅤ,Hind Ⅲ,HpaⅠ,PstⅠ,SalⅠ,ScaⅠ and XhoⅠ,were used to study the mtDNA restriction fragment length polymorphism (RFLP) in 6 individuls of the Hainan and Xuwen yellow cattle from Hainan and Guangdong.Only (SalⅠ) out of 14 restriction enzymes disclosed mtDNA polymorphism within the Hainan yellow cattle,of which the C pattern (15.0,1.3) has not been reported previously.The restriction patterns generated by 13 of the enzymes in Xuwen yellow cattle were identical with those in Hainan yellow cattle.The halotypes of the 6 individuals were almost A-A-A-A-A-A-A alone represented by Bos indicus.Our results showed monophenetic maternal origins of these two breeds of yellow cattle,and suggested that the genetic diversity within the two breeds is remarkably scarce.The low variation and monotoneous population genetic structure indicated a close relationship between the two breeds,which supported the hypothesis that Hainan yellow cattle and Xuwen cattle were from one breed named Leiqiong yellow cattle.