The structure development of drawn poly(trimethylene terephthalate) PTT as a function of draw down ratio and drawing temperature was studied. The special effort was made to find out the effect of structural development on thermal properties and crystallinity in drawn PTT. The changes in shrinkage ratio and mechanical properties were understood base on the level of crystallinity and orientation of the drawn PTT. The stress induced crystallization caused the increase in glass transition temperature and the decrease in cold crystallization temperature and enthalpy. The crystallinity and orientation were dependent upon the level of applied stress level as well as chain flexibility at high drawing temperature. The drawing resulted in the increase of shrinkage ratio but it was minimized by increasing of crystallinity. The development of orientation resulted in increasing modulus and tensile strength while decreasing elongation at break.