At this time, the material made from plastic is widely used because it has strong and inexpensive properties. However, the amount of plastic waste is an environmental problem in every region. One way to overcome is to create environmentally friendly plastics that can decompose naturally. The purpose of this study was to prepare and investigate the tensile strength, thermal resistance and scanning electron microscopy (SEM) morphology observations of polylactic acid (PLA) and cassava starch (CS) with cellulose paper from sugarcane bagasse (CPSB) as filler. The fabrication process uses the solvent casting method with constant PLA and CS concentrations of 80% and 20% with variations in the CPSB mass fraction of 0.5%, 1%, 1.5%, and 2%. SEM observations showed that the mixture of PLA and CS had poor bonding due to the different hydrophobicity of the two materials. The content of CS causes agglomeration. The addition of CPSB reduces the tensile strength from 21.96 to 16.56 MPa and the modulus of elasticity from 96.75 to 74.90 MPa. The thermal resistance of the composite mixture increases with increasing CPSB load.