The 10 bamboo species for cloning lea3 gene concern two superfamily, six families and three subtribes，they are Thyrsostachys siamensis,Bambusa multiplex, Bambusa textilis, Dendrocalamus farinosus, Neosinocalamus affinis, Dendrocalamus semiscandens, Phyllostachys heterocycla, Chimonocalamus delicates, Pleioblastus amarus, Sasa fortunei. In the branch model and branch site model test, found that different bamboo species containing lea3 gene under different selection pressure, purifying selection function is in dominant (omega<1). In the site model test, detected a total of 18 significant positive selection sites, account for 111% of the total amino acid number. Locating the 18 significant positive selection sites, found 15 sites located 11 amino acid tandem repeat sequences areas, this means that 11 amino acid tandem repeat sequences areas of lea3 gene than in other regions more easily affected by natural selection effect. At the same time, based on the results of the site model test, through located these intence purifying selected sites, found a long no purifying selection sites area in 11 amino acid tandem repeat sequences.