This study was done to investigate the enzyme-histochemical localization and characteristics of alkaline and acid phosphatase related with metabolism in sparganum and adult of Spirometra erinacei. By the enzyme-histochemical assay, the alkaline and acid phosphatases were localized in the tegument and subtegumental musculature of sparganum and adult, but not in the parenchyma. The activities of alkaline phosphatase were stronger in the tegument than in the subtegumental musculature, and activities of acid phosphatase were stronger in the tegument of adults than those of sparganum. The 2 isozymes of alkaline and acid phosphatases were separated from s-sparganum (from snake) and r-sparganum (from experimentally infected rats) respectively, but 4 isozymes of Alp and 3 isozymes of Acp were separated from adult worms by electrophoresis. In isozyme Alp, the 66 kDa was the common isozyme, but 130 kDa isozyme of Acp was the common isozyme in spargana and adult worms. By isoelectrofocusing, 4 isozymes (PI 7.9, 7.7, 6.5 and 6.3) and 2 isozymes (PI 7.9 and 7.7) of alkaline phosphatase were separated from adults and spargana, respectively. In the stability against heat, activity of alkaline phosphatase was denatured perfectly after heating at 90 degrees C for 40 seconds. The optimum pH and temperature for activity of alkaline phosphatase were about pH 10 and 50 degrees C, respectively. The maximum activity (unit) of alkaline phosphatase was 22.0 in s-sparganum, 25.0 in r-sparganum and 215.0 in adult worms, so that the maximum activity was revealed higher in adults than spargana. As the result from above, we observed that alkaline and acid phosphatases were functioned mainly in the tegument and subtegumental musculature, and the isozymes of phosphatase were activated differently according to habitat of the parasites. The spargana and adult worms carry out the parasitism by adapting themselves to parasitic circumstance with these enzymes.