Polylactic acid (PLA) fibers have properties that are high crystallization, good flexibility, heat-resistant and very durable. This product has superior performance and may replace polyester fibers in daily use. The main advantage is that PLA is biodegradable and eco-friendly. On disposal a microorganism will be released to allow fermentation and breakdown the high polymer chain within the fiber. It will decompose causing non-crystallization of the fiber that then becomes a low molecular compound. It will crack the fiber and the surface will corrode and wrinkle. Although it is similar to PET in various aspects, dyestuffs which give good dyeing results on PET do not necessarily result in good color yield and fastness properties on PLA. Finally, it will turn into water and carbon dioxide. Therefore, it will not cause more pollution in the environment. In this thesis, we will try to synthesis high molecular disperse dyes (as shown photo), so we can make dyestuffs products that have a strong Van der waals force with the fiber to increase the combination of dyestuffs and PLA. In order to determine that the dyestuffs have synthesis correctly we used spectrometric identification of organic compounds, utilizing K/S value to compare the dyeing of the fabric under every condition. Finally, we checked degradation of the fabric under temperature, using observation through an electronic microscope, and then using an atomic force microscope to set up a dyeing model for polylactic acid fibers. Keywords: Polylactic acid, crystallization, dyeing model, disperse dye, fastness