Based on the closest packing theory, combining Funk-Dinger model with Microsoft Excel Solver Tool determines the weight of cementitious materials which is used to develop the UHPFRCC. Using limestone to improve the flowability can determine the final mix proportion. Experimental results show that the maximum density theoretical model based on the Dinger-Funk equation can be applied to the mix proportion design of UHPFRCC; Hybrid fibers can increase the compressive of UHPFRCC and decrease flexural strength; compared with the UHPFRCC in corporation of 2% steel fibers, addition of synthetic fibers reduces the compressive strength and flexural strength of UHPFRCC.