The first results of an analysis of the spatial variations along and across the ENLR of NGC 4151 are presented. The excitation of the gas clearly decreases with distance from the nucleus. The mean energy of the ionizing continuum deduced from the He II/H-beta ratio is compatible in the SW with a power law of spectral index -1.5. The angular variation of most of the spectral diagnostics in both 'blobs' SW, as seen from the nucleus, is presented. There is a clear tendency for likeness produced in the semionized regions of the optically thick brightness of the blob.