||The study of single-phase solid ER “fluids” is considered as a branch of study of ER fluids. Due to the study of single-phase solid ER “fluids” faces many extreme difficulties, such as single-phase solid ER particles cannot form suspensions in gravity environment. Comparing to the study of two-phase ER fluids, it is relatively under-developed in both scientific and applied fronts. In this thesis, a microgravity experimental method for single-phase ER fluids study is introduced. This high sensitive electrorheological experimental setup is designed particularly for single-phase ER fluids drop tube microgravity experiment. We have successfully fabricated the experimental setup and tested the system with drop tube experiments. This experimental setup consists of a microgravity electro-rheometer, an imaging system, an experimental controller and the supporting parts. 100 microns glass particles are selected as ER material for the test experiment of the experimental setup. It is now proven that the experimental setup could work functionally and stably for repetitive drop tube microgravity experiments. This microgravity experimental method has the potential to greatly improve the study of ER fluids (both single-phase and two-phase ER fluids), the development of single-phase ER material and the development of applications of single-phase ER fluids.