T(4-TMAP) P [?,?,?,?-tetrakis-(4-trimethylammoniunphenyl)Por-phine] has been used for the colorimetric determination of copper in grain. The results of this method are in agreement with those of atomic-absorption spectrophotometry and the ordinary spectrophotometry. The method is very simple, accurate and rapid. The recovery is 94.2%-105.8% and the coefficient of variation is 1.6%-4.9%.