Objective To investigate the genetic diversity of the original population of Z:ZCLA Mongolian gerbils by biochemical markers.Methods 19 biochemical loci as markers were used to detect the genetic variation in the conventional closed colony of Z:ZCLA Mongolian gerbils.Results The loci Es-1,Car-2,Hbb,Gpi-1,Cs-1,Ce-2,Idh-l,Mod-1 had only one allele,while the loci Es-2,Es-3,Es-4,Es-6,Es-8,Es-9,Es-10,Gpd-1,Pgm-1,Trf,Akp-1 had two to four alleles,respectively.The average heterozygosity,allele number and polymorphism information content were recorded as 0.512,3.0 and 0.455 respectively.Conclusion The analysis of polymorphism information content on 11 biochemical gene marker loci of this conventional closed colony of Z:ZCLA Mongolian gerbils revealed the genetic diversity at a moderate level.