Synthesis of biodegradable composite polymer by adding tapioca meal as filler to a thermoplastic polymer has been done using blending method. The thermoplastic polymer used in this research is a polypropylene with melt flow 10 (PP10), and 35 (PP35). The composition of tapioca were 50, 55, 60, 65,70 and 75% w/w. Sample characterization carried out involved mechanical testing, thermal analysis, microstructure analysis and the biodegradability test. The tensile strength test result shows that the mechanical property of the sample decreases with the increasing of filler content, while the thermal analysis result shows that the melting point of the sample does not show the significant change. The microstructure result shows that between thermoplastic and filler inside the composite polymer was mixed homogeneously for composition of the filler under 50 percent. For the filler composition greater than 50 percent, the filler was not mixed homogeneously but tend to agglomerate. From biodegradability test result seen that both of the polymer composite of polypropylene sample namely, PP10-Tapioca, and PP35-Tapioca can be used as environmental friendly packaging materials.