Abstract: A positive interference of copper on lead was found with determination of lead by the full wavelength range direct reading ICP-AES.For instance,the Pb 220.3 line was interfered by the Cu 221.810 line.The interference is generally impossible in that the two lines are far apart for the classical spectrum.The solid-state array detector and echelle grating was applied to the full wavelength range direct reading ICP-AES.The vertical interference was broken out in the two bands.The interference factor correction method or spectrograph in the VIS segment can be used after clearing sources of interference.