The separation and conversion of palm palmitic acid to polyester was carried out. Firstly, the separation of saturated fatty acids (SFA) from palm fatty mixture acid (PFAM) by methanol crystallization was studied. Further separation and purification of PA from SFA by another methanol crystallization was also studied and optimized using response surface methodology (RSM) with D-optimal design. Then PA was converted to palm palmitic acid based polyester. In general, the synthetic polyester could be used as internal plasticizer in bio-based industry.