Fortyfour male Kunming mice, weighing 20-25g. were used. The HpD was injected (10mg/kg) into the caudal vein of 32 mice individually. After 48 hours, the kidneys were radiated directly by the dye-laser for 10 minutes (630nm, 250-300J/cm~2). Then, the kidneys were observed at different times. 12 normal male mice served as control. The experiment demonstrated that when HpD was activated by laser, it could produce the necrotic effect on the renal tissues. The different structures of the kidney showed different susceptibility to HpD-laser. The proximal convoluted tubules and capillaries were injured earlier than the distal convoluted tubules and the collecting tubules. The first morphologic changes observed electron microscopically were the swelling of mitochondria and the formation of vesicles on the cell membrane. Finally, they were completely disrupted. The damages of lysosomes, endoplasmic reticula, ribosomes and cell nucleus followed. The activity of some enzymes in the kidney were inhibited. The sequence of the extents of the enzymes being inhibited was AkP, AcP, Cytox, SDH. The mucopolysaccharides ran off the brush border in proximal convoluted tubules. The results of this study suggested that the various susceptibilities to HpD-laser are chiefly due to the different structures and their functional conditions in the kidney. The main photodynamic effect is presented as the injury of the membrane system of the cell.