Dielectrophoresis is a technique of using high-frequency electric fields to manipulate dielectricparticles. This work applies this technique to study the changes of intracellular properties in responseto environmental changes. In a number of plant cells, chloroplasts change their positions foroptimizing photosynthetic light absorption. Only between 2 and 20% of the light energy absorbed byalgae and higher plants is actually used in CO2 fixation. Comparing with other micro-manipulativemethods, dielectrophoresis is a relative simple method for investigating the microscopicmechanisms involved in chloroplast repositioning.Leaves of Egeria densa were subjected to different lighting conditions before conductingdielectrophoresis. Under dim light, chloroplasts situate on the periclinal wall. Under high-intensitylight, chloroplasts move from the periclinal wall to the anticlinal walls. Under electric fields,chloroplasts treated with different lighting condition exhibit different motions. It is expected thatactin configuration as well as chloroplast-actin binding strength contributes to the repositioning ofchloroplasts.