In additive manufacturing, indirect laser sintering is used to process and fabricate ceramic materials using a polymer-ceramics green body. The mechanical strength of the green body is important to hold the shape and to enable the use of laser with low power density during the laser sintering process. Because the microstructure of the green body will considerably affect the density of the final product, this study demonstrated a feasible controlled formation of Poly (methylmethacrylate) (PMMA)-Al2O3 composite particles by an electrostatic assembly method that was used for the fabrication of the green body with improved mechanical properties, which were determine using an indentation test. The controllable homogeneous decoration of desired submicron-sized PMMA particles on Al2O3 particles allowed an effective use of PMMA additives while exhibiting considerable mechanical property improvement of the green body compared to poly(vinyl alcohol)-bonded Al2O3. The findings of this study show good potential of green body formation with improved strength for ceramics fabrication via indirect laser sintering.