Abstract:The equation for calculating Bladder dimension is derived based on the relationship between bladder pressure and the inner diameter of composite bearing cylinder. Effects of bladder pressure on the thickness, fiber volume fraction and bending properties of composite bearing cylinder were investigated. The composite bearing cylinder was manufactured by bladder-assisted resin transfer molding(BARTM) process. The experimental result shows that higher bladder pressure decreases thickness of composite bearing cylinder, increases fiber volume fraction and improves the bending properties. This indicates that composite bearing cylinder can be manufactured with precise inner diameter by BARTM process with a proper bladder pressure.