This paper deals with the effect of natural pigments (chlorophyll and anthocyanin) on the secondary bonds in ( poly methyl methacrylate PMMA), which play an important role in the physical and chemical behavior of it. Natural pigments extracted from plants by a simple method and blended with PMMA powder in different ratio of natural pigments, and the properties of the blend were determined and compared. The extracted pigments were characterized by UV- visible spectroscopy and Fourier transform infrared spectroscopy (FTIR). The blend of PMMA with pigments were characterized by FTIR, X-ray diffraction (XRD), differential scanning calorimetry (DSC), hardness, and density. The results show that anthocyanin shows higher depression in glass transition temperature (Tg) of PMMA than chlorophyll pigment, where the maximum effect of chlorophyll is 3%. The obtained Tg used in calculations depending on molecular models which its content the simplest idealized model of a linear molecule is the chain model without branching. The hardness and density of PMMA decrease as anthocyanin and chlorophyll percent increases. All these results were contributed to that chlorophyll and anthocyanin act as plasticizers by effecting on secondary bonds of polymers.