Study shows that most facial fractures happen in the mandibular region, affecting the aesthetic and functionality of the victim's face. Miniplate and screw system is the most common method to treat craniomaxillofacial fractures problem. Biodegradable miniplate and screw have several advantages over metal miniplate and screw. As one of the efforts to improve biodegradable miniplate and screw, this study focused on analyzing the mechanical strength comparison between three biodegradable materials, which are poly (l-lactic acid) (PLLA), AZ31 magnesium alloy, and sago-PLA, using finite element analysis through comparing stress distribution, deformation, and safety factor of the structure. The simulation uses two four holes miniplate in mandibular fracture with ramped force input from the mandibular structure of 460.91 N in molar areas and 146.5 N in incisors area. The result shows that AZ31 magnesium and sago-PLA (S-PLA) could be considered as possible substitutes for PLLA with average Von Mises stress in maximum force input with 5,4968 MPa using PLLA, 5.5365 MPa using S-PLA20, and 17.854 MPa using AZ31. This simulation also shows the maximum total deformation for each material with 0.57932 mm using PLLA, 0.57909 mm using S-PLA20, and 0.53464 mm using AZ31, which happened in the middle of the inferior miniplate.