A large number of studies on compressive properties of fiber assemblies have been carried out by many investigators. But studies on its temperature dependency have scarcely reported in spite of its importance. Therefore, from this point of view, we studied on compressive properties and its temperature dependency of columnar fiber assemblies consisting of cotton, viscose and polyester staple fiber respectively, and obtained the following conclusions. (1) The logarithmic relations between compressive stress, Pc (g/cm2) and volume ratio, λ (=real volume of fibers/apparent volume of fiber assembly : no dimension) in each fiber, are all straight lines with different slopes in two specially extents of λ respectively, and these straight lines are connected by very slow curves in the narrow extents of λ. (2) The compressive property in the extent which the relation between log Pc and log λ is straight line is indicated the following formula, Pc=Y (Xλ) nwhere X, Y and n are constants determined by the kind of fiber, temperature and the degree of compression, and in this study the constants, X, Y and n, in the formula mentioned above are given as follows : X=23.1Y=22.0 (1-e-0.045t) n=at3+bt2+ct+d (20≤t≤90) where t is temperature (°C), and also a, b, c and d are constants determined by the kind of fiber, temperature and degree of compression.