The pneumatic hydraulic braker which is attached to an excavator is widely used in the construction industry field, and is increasing its capacity and performance because many users want high power and efficiency of the pneumatic hydraulic braker. The structure of a pneumatic hydraulic braker is composed of piston, rod(chisel), back head gas chamber, and directional control valve. The performances of a pneumatic hydraulic braker are impact force, impact energy, impact rate, etc., and depend on the hydraulic components and system. This paper will argue that the performances are investigated and analysed using the AMEsim program which is used in hydraulic and pneumatic system. It is shown that the performances of the heave duty pneumatic hydraulic braker are good in many fields relative to other brakers during the simulation process