Synthetic polymers have become essential in our life, nevertheless, the high production and the low recycling around the world have caused serious problems of contamination in soil and water. In addition, its fragmentation into microplastics in environmental conditions has exacerbated the ecological problems due to its possible ingestion by organisms and its high capacity to transport and release a wide variety of organic pollutants. Photo-Fenton process was used to evaluated its capacity to degrade PA6.6 microplastic under simulated solar irradiation and natural solar irradiation plus LED visible light in order to get a best knowledge about its behavior in environmental conditions. PA6.6 was degraded for 7 h through photo-Fenton process under simulated solar irradiation. Superficial defects were observed along the PA6.6 microplastic after degradation experiments. However, FT-IR analysis did not show the formation of additional bands which indicated the formation of new products. DSC analysis showed changes in the melting point of the PA6.6 after the photo-Fenton treatment at different times. The assays carried out under natural solar irradiation showed lower degradation of the PA6.6 under the same experimental conditions, nevertheless, it was observed an increase of the specific surface area 90 times higher in the PA6.6 treated for 10 h.