Three dimensional (3D) printing technologies have been developed within recent decades and have been demanding for today practical application because of its advantages such as low cost production and easy and simple to use. However, there are still weaknesses in the printing result and processing, including the process efficiency, limited resolution especially for complex design of resulted product, and optimization of the mechanical properties of the filaments used. This study aimed to analyze the effect of variations in the internal geometry on the mechanical properties of 3D printed object using PLA materials. The printed object varied by geometrical shapes and thickness of each geometry. Internal shape geometry used is a triangle and honeycomb, with variations in the size of each symmetry axis of the goemetry are 4.5 mm and 9 mm, and the thickness variation between objects are 1 mm and 2 mm. Test results show that the best performance obtained by measuring its tensile and flexural strength is the sampel with triangle geometry of 9 mm geometrical size and 2 mm of thickness. The tensile strength and flexural strength values of the object are 59.2996 MPa and 123 MPa respectively.