Abstract:A 398-bp plantified encoding fragment of porcine α-lactalbumin， was cloned into plasmid under the control of the cauliflower mosaic virus 35S promoter． The expression cassette was introduced into A rabidopsis with Agrobacterium mediated transformation． Some herbicide-resistant lines of transform ed A rabidopsis were selected． The gene integration of chromosomal DNA level were confirmed in regenerated plants． All of them are positive for porcine α-lactalbumin gene via genomic DNA PCR． The expression at the protein level could be confirmed only in the transgenic A rabidopsis．The arabidopsis-expressed lactalbumin (LA) migrated in SDS- PAGE with identical mobility to human LA prepared from human milk． indicating that the LA was correctly processed to yield a mature protein in plants.