The geometrical parameters of spun yarn such as orientation angle, radial position of fiber and length of fiber were measured using the tracer fiber technique and correlations between them were investigated at five different numbers of twist of yarns, i.e., 420, 470, 570, 770, 970 tpm. Length of fiber(L) increased with the value of orientation angle($ heta$) of fiber. However, there were no correlation between length of fiber and radial position of fiber(r/R) as well as between orientation angle of fiber and radial position of fiber. Not only the orientation angle but also its relative frequency of fibers were measured using the tracer fiber technique. Their frequency curves were followed normal distribution and the shape of curves were shifted to higher orientation angle with number of twist of yarns. The mean value of orientation angle of fiber at each radial position showed an increase with the radial position of fiber. The initial tensile modulus of spun yarn determined experimentally showed lower value than theoretically determined for the yarns with low twist levels of 420, 470, 570 tpm. These results can be explained by the slippage between fibers.