Polyester-type polyols with a single benzene ring and a double benzene ring attached to a polyethylene glycol (PEG) moiety on only one end (PT series and PTET series), or both ends (PTP series and PTETP series), or attached to a PEG and an ethylene glycol (EG) moiety each on the separate ends (PTE series and PTETE series), were synthesized, and absorption behavior of the polyester-type polyols toward polyethylene terephthalate fibers (PET) was investigated. The results showed that all the synthesized and tested polyols structurally belonging to the single benzene ring series (whether PT, PTE, or PTP series) and a double benzene ring system with PEG attached on both ends (i.e., the PTETP series) fit nicely to the dual sorption mode of a combination of Henry type and Langmuir type. However, the other double benzene ring series, either with only PEG on one end (PTET series) or with a PEG and an EG moiety each separately attached on the two ends (PTETE series), displays a Freundlich-type sorption. Furthermore, it was found that the HLB value of polyols, and the disposition of the PEG moiety in the structure of polyols, are also quite important in effecting the absorption parameters.