In the present work, we found that single-walled carbon nanotubes (SWCNTs) could be straightened by poly(9,9-dioctylfluorene) (PFO) chains with both alpha- and beta-conformations in different solvents. UV-vis and PL spectroscopic studies confirm that there exists pi-pi interaction between SWCNTs and PFO. SWCNTs are helically wrapped by the adsorbed PFO chains, which is different from the coaxial interaction between SWCNTs and poly (3-hexylthiophene) (P3HT). More stretched PFO beta-conformers have a stronger interaction with SWCNTs, and the interactions between SWCNTs and PFO slightly improve the conjugation length of beta-conformers in turn. We proposed that the straightening of SWCNTs by adsorbed rigid conjugated polymers is irrespective of interaction mode between them.