Abstract: The self-made fiber compression device was designed to investigate effects of compression and rebound process and electrode location on electrical resistance measurement of cotton fiber assembly. It is intended to make reference for improving the accuracy and reproducibility of the measurement of moisture regain and electrical resistance of cotton fibers. The experimental results revealed that electrical resistance of cotton fiber assembly is approximately inverse proportion to the volume density of the fiber assembly. At higher density of fiber assembly, density of fiber assembly can be obtained by compression and rebound. At the same density of fiber assembly, volume resistivity in compression process is less than that in rebound process. There is difference between volume resistivity of cotton fiber assembly in compression direction and in the direction vertical to compression direction. With the increase of density, the difference between them increases to some extent. At applied voltage of 10 V, volume resistivity of cotton fiber assembly in compression direction is larger than that in the direction vertical to compression direction. Higher density of fiber assembly is in favor of resistance testing for cotton fiber assembly, Stable and accurate results can only be obtained in compression process.