The present invention relates to a method for visualizing GFP expression in callus, various tissue and organ of the transgenic plants as image and system using the same. The said method needs no other additional genetic product, substrate or cofactor and can detect very simply and quickly GFP expression by using the said system of the present invention consisting of a CCD camera, a light source, band-pass filter and data processing computer, so it provides many advantages for selection of transgenic seeds, for studying of gene expression in the tissue or organ of plants, or for studying of specificity of each development step.