For various applications, it is essential to enhance the colloidal stabilization of carbon nanotube (CNT) dispersions. Here, the polymers with carbazole pendants of poly(4-(N-carbazolyl)methylstyrene-bl-poly(ethylene glycol) methyl ether methacrylate) (PCMS5-b-PAPEG73 and PCMS16-b-PAPEG43) and PCMS30, synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization, were used for noncovalent functionalization of multiwalled carbon nanotubes (MWCNTs) in tetrahydrofuran (THF), offering efficient colloidal stabilization. Meanwhile, the adsorption of polymers onto MWCNTs was investigated. The results showed that the MWCNTs decorated with these three polymers in THF exhibited different colloidal stabilization and adsorption capacity. Moreover, the MWCNT dispersions could be stabilized for days and their colloidal stabilization elevated with the increase of polymer concentrations. The block copolymer PCMS16-b-PAPEG43 exhibited the optimal adsorption and dispersion capability for MWCNTs. These findings imply that PCMSm-b-PAPEGn will be a desirable dispersant for optimizing the stabilization of CNT dispersion, making carbon nanotubes (CNTs) achievable in different applications.