【Objective】A new bivalent plant expression vector， named pCambia1300-cbcor15a-bar， was recombined by inserting two genes， i.e. Cbcor15a and eGFP， into the vector pCambia1300-bar and replacing the promoter CaMV 35s with Ubi-1. 【Method】Based on the multiple cloning sites of the expression vector pCambia1300-bar， the primers were designed according to the nucleotide sequence of gene Cbcor15a and eGFP and the promoter Ubi-1， and then the fragments of the genes and promoter were inserted into the vector pCambia1300-bar. The plasmids of the vector pCambia1300-cbcor15a-bar were transduced into onion epidermal cells via particle bombardment. The results were observed through fluorescence microscopy and confocal laser scanning microscope， respectively. 【Result】Compared to onion epidermal cell with pCambia1300-bar， onion epidermal cell transduced with the recombinant vector plasmid had a very bright green florescence. 【Conclusion】Downstream cold-induced gene Cbcor15a and reporter gene eGFP regulated by up-stream promoter Ubi-1 were expressed efficiently， which could ensure the construction of Cbcor15a.