The invention provides a production device and a production method for soft, clean and pure yarns. An upper rubber roll in each drawing roller pair is connected with a pressurizing
assembly through aconnecting vertical rod which can be stretched or shortened, so as to realize pressure adjustment between the upper rubber roll and a lower roller in a
spinning process through stretching or shortening control of the connecting vertical rod, and thus pressure adjustment of
fiber strands between the upper rubber roll and the lower roller in a
spinning process is realized. Thus, selection of fiberswhich can slide mutually in the
fiber strands is realized. Therefore, on one hand, gradual
change control of
yarn density of spun yarns is realized, and on the other hand, through controlling differences of
yarn density in the
fiber strands, a process of few fibers in low
yarn density wrapping multi-fibers in high yarn density in a twisting and yarn forming process is realized, so that integratedstructure control of inner-loose and outer-tight of yarns is realized, and development of yarns which are smooth and clean on surfaces and soft is realized.