Clearly knowing the structural responses of polymers to the treatment conditions is essential to regulate their final properties during industrial processing such as spinning, extrusion, injection, and blow molding. In this work, we reported the changes of hierarchical structure in poly(butylene succinate-co-terephthalate) (PBST) copolymer upon application of synchronous stimuli via uniaxial stretching at varying temperatures. The lamellae melting and the transition of crystal structure from to form in PBST copolymer always presented at the early stage of the deformation at different temperatures. The lamellae oriented to about +/-(40-50)degrees direction as the yielding response to the stimuli. Upon further stretching, the oriented lamellae were freshly and progressively formed at high temperature, whose morphology was controllable by regulating the synchronous stimuli. Furthermore, a schematic for the structural responses to the synchronous stimuli was proposed. The structural responses of PBST copolymer under such synchronous stimuli are beneficial to tailor the final properties of the products in the form of fibers, films, plastics, and so forth, which also can provide new insights into the design and development of other copolymers. (c) 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015, 53, 640-649