In order to detect plant thykaloid protein phosphorylation in vivo rapidly, a new approach was introduced by using INDIA^TM phosphorylated protein probe. Eight phosphoprotein bands were detected by this method in the thylakoid membranes isolated from pea leaf discs illuminated at 400 μmol·m^-2·s^-1. The molecular masses of those phosphoproteins were 65 ku, 45 ku, 36 ku, 33 ku, 30 ku, 29 ku, 20 ku and 10 ku. Respectively by using various polyclonal antibodies, those phosphoprotein bands were identified as phosphorylated D1/ phosphorylated D2 dimer, PSⅡ core phosphoproteins, CP43 (45 ku), D2 (36 ku), D1 (33 ku) and psbH gene product (10 ku), and the light-harvesting complex (LHCⅡ) phosphopolypeptides, LHCB1 (30 ku) and LHCB2 (29 ku). A comparison was made between this new approach with other methods of detecting phosphoprotein such as radiolabeling experiment or immunological blot using phosphothreonine antibody.