The cross-section shape, longitudinal self-crimping configuration of various PTT (Polytrimethylene terephthalate)/ PET (Polyethylene terephthalate) filaments were observed and measured via microscope. The crimp parameters of the filaments, including helixes pitch, crimp radius, crimp curvature and regular crimp proportion were calculated, and the relationship between crimp parameters and self-crimping configurations of PTT/PET filament was analyzed. Various shapes of PTT/ PET fiber cross-section were detected such as round, peanut, dog bone and pear like shapes. Crimp configurations were found not always regular spatial helix along the longitudinal direction of filament and had significant difference according to the fact whether the filament was undergone textured process. With the length rate of the long axis to the short axis of crosssection increasing, the crimp curvature of filament will also increase. The helix pitch and radius will increase while the crimp curvature will decrease with the increasing linear density for the same cross-section shape of PTT/PET filament.