Based on rigorous solutions of steady multi-level rate equations, we made theoretical analysis of the behavior of CW optogalvanio signals. Acoording to the experimental results, the concept of an equivalent local electron density and its relation with the I-V curve of an HCD lamp is proposed. Experimental data of the anormalous optogalvanio spectroscopy and the sensitivity fluoresenoe of Cu irradiated by a CW laser (578.2nm) are shown for the first time. These results, together with the optogalvanic experimental data of Ne 1s—2p levels reportod else where, bear out the theory satisfactori]y.