Abstract: Based on the analysis of geo-historical data and gel electrophoresis measurement, the genetic diversity and genetic structure of 11 populations of three species were studied, which included Fagus engleriana, F. pashanica and F.lucida.The genetic diversity and genetic structure of 7 Eurasian beeches with the changes of latitude, longitude and altitude were discussed.Ten allozymes including peroxydase (PX₁ and PX₂), phosphogluconate dehydrogenase (PGD), acid phosphatase (ACP₁and ACP₂), superoxide dismutase (SOD), glutamate oxaloacetate transaminase (GOT₁ GOT₂ and GOT₃), isocitrate dehydrogenase (IDH), phosphate glucose isomerase (PGI), menadione reductase (MNR), phosphoglucomutase (PGM₁ and PGM₂) and malate dehydrogenase (MDH₁ and MDH₂) were selected to analyze the genetic similarity, genetic diversity and genetic distance of the beeches distributed both in Europe and Asia.The results show that the allelic frequency varies with seasonal and geographic conditions, and both F.lucida and F.engleriana contain many special allelic genes.It can be concluded that the two species are widely distributed but relatively independent on the other species;F.lucida and F.pashanica have a close genetic relationship while F.engleriana has a much far relationship with F.lucida and F.pashanica.F.sylvatica has a far relationship with all the three Chinese species.Finally the allozyme spectrum and dendrogram of Eurasian beeches were made.