1. The author put forward the improved method of siderocyte staining method with o-phenanthroline. 2. Standing human and canine blood at the room temperature under the aseptic condition after the non-coagulating treatment, siderocyte increased temporarily and the increase delayed, but the measure was a little much. 3. The increase of siderocyte was promoted with the rise of temperature and it was controled with the remarkable fall of temperature. 4. The temporary increase of siderocyte on the addition of equal dosis of physiological saline solution into blood and on the production of erythrocyte-physiological saline floating solution was same to that of the non-coagulating blood. 5. The remarkable increase of siderocyte was not observed on the erythrocyte-dissolving solution in both of canine and human blood. 6. The formation of siderocyte was promoted with phenylhydrazine, but the increase of siderocyte was temporary. 7. The formation of siderocyte was also promoted with l-ascorbic acid. 8. Nitrobenzol had no effect on the formation of siderocyte. 9. The formation of siderocyte was chiefly participated in the decomposition process of hemoglobin in erythrocyte and the acceleration of osmosis of the erythrocyte membrane promoting it.