Two genes, the replicase gene from Banana bunchy top virus and coat protein gene from Cucumber mosaic virus, were firstly fused together with PCR, and were inserted into a plant expression vector-pBI121. The plant expression vector was transformed to Agrobacterium tumefaciens LBA4404. As a result, the engineered agrobacteria containing pBI121.FBC were gotten, and would be further used to develop a engineering banana variety resistant to two kinds of viruses.