Environmentally friendly plastics can be degraded biologically in an anaerobic environment. This plastic is synthesized from starch such as sago starch which is available in abundance. In the form of bioplastics, its mechanical properties are still not compared to conventional plastics derived from crude oil, so its application is limited. The incorporation of filler material increases its mechanical properties, one of the selected fillers is hemp fiber as used in this study. Thermoplastic starch from sago with flax fiber as a filler and the addition of Polypropylene to improve mechanical properties with a certain composition to maintain its natural biodegradability. The mechanical properties analyzed were tensile strength, elongation and modulus of elasticity. Water absorption tests were also carried out to observe the water resistance properties. The results of the tensile strength test showed that the best tensile strength value of 9.32 Mpa was obtained at the addition of 35% fiber with a TPS: PP ratio of 1:1.5. The same conditions were obtained for the percent elongation with the results of 10.16% and the modulus of elasticity was 91.73 Mpa. Water absorption showed that 55% filler gave the lowest water absorption, namely 4.41% at a ratio of TPS: PP 1:0.5. The addition of fiber filler into the bio-composite affects the tensile strength, elongation and modulus of elasticity, the higher the volume of filler entering the bio-composite, the lower the value of tensile strength, elongation and modulus of elasticity, or vice versa. The ratio of addition of polypropylene matrix is also influential, the higher the ratio contributes to the tensile strength, elongation and higher modulus of elasticity. High water absorption capacity will reduce the performance of biocomposite, so the lower the water absorption ability, the better the quality of the biocomposite product and the wider its application