Abstract: The study of the surface pressure area isotherms of two kinds of CuPc monolayers spread at air/water interface has been carried out.The conditions of forming films for CuPc monlayers have been found to be highly depending on various experimental parameters,e.g.intial spreading quantities of CuPc, spreading solvent,barriar speed and arachidic acid inbeding.Optimizing these parameters,the quality of the LB films can been improved.