Dielectrophoresis is a technique of using high-frequency electric fields to manipulate dielectric particles. This work applies this technique to study the changes of intracellular properties in response to environmental changes. In a number of plant cells, chloroplasts change their positions for optimizing photosynthetic light absorption. Only between 2 and 20% of the light energy absorbed by algae and higher plants is actually used in CO2 fixation. Comparing with other micro-manipulative methods, dielectrophoresis is a relative simple method for investigating the microscopic mechanisms involved in chloroplast repositioning. Leaves of Egeria densa were subjected to different lighting conditions before conducting dielectrophoresis. Under dim light, chloroplasts situate on the periclinal wall. Under high-intensity light, 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 that actin configuration as well as chloroplast-actin binding strength contributes to the repositioning of chloroplasts.