Phaneroplasmodium of myxomycetes can be served as a model material for studies on cyclosis. Because of its stabilized ectoplasm,bubbly motile endoplasm and large size,the observation and measurement of the velocity of its protoplasmic streaming became easier. Hydrological buoy method to measure the velocity of streaming was described in this paper. The results showed that the streaming velocity among 9 bubbles selected randomly varied from 25. 83 μm/s to 289. 05 μm/s,and the average velocity was 190. 01 μm/...