A novel plant virus vector and a method of gene expression into plants are provided, and the present invention relates to a plant virus vector characterized in that a part of the sequence of the 2b region of the RNA2 molecule of the Cucumber mosaic virus (CMV) is deleted; the aforementioned plant virus vector characterized in that the region from the StuI site to the stop codon of the 2b ORF of pCY2, which is an infectious clone of CMV-Y RNA2, is deleted; and a method of gene expression in plants characterized in that a foreign gene is introduced so as to be stably expressed in a plant using the genetic recombinant. This vector is useful as a plant RNA vector for causing stable expression of foreign genes.