This paper presents the results of some experiments performed using the power system bands directly from the card to the rotor spinning machine and the spinning system used by passing the lanes on two passages mill and fed to the spinning rotor. In this study we analized the influence of technological parameters of the preparation drawing on the assessing indicators for the tensile strength of the Nm20, Nm24, Nm27 Nm34 and Nm40 yarns. The fineness range studied was made of three fiber mixtures of different varieties of cotton, coded as follows: A1-85% Soviet cotton+15% Chinese cotton medium II; A2-100% Turkish cotton medium III; A3-100% American cotton mdium IV. The method of preparation of the bands which are to be powered to the rotor spinning machine, respectively with the aggregate pile-card and the powered bands directly to the rotor spinning machine and the adding of two rolling mill, detemines different structures of bands and different degrees of untangling and orientation of the fibers, which influences the quality of the obtained yarns. This study reveals a considerable improvement of the tensile properties when the yarns are made from rolled band, which is explained by the high degree of correction and parallelization of the fibers of the rolled band, which allows a greater participation of fibers with their resistance to the resistance of the yarns.