A dynamic and hydraulic analysis on common-rail injectors using Bond Graph Simulation Program (BGSP) was made. BGSP is based on the Bond Graph method of hydraulic system modeling, which has an advantage in handling multi-energy domains such as common-rail fuel injection system.After the verification of BGSP, analysis was made on a few concepts of common-rail injectors. Pressure traces of the control chamber for each injector concept was obtained. Through these analysis, the key phenomena were identified.Although the optimization has not been done yet, compatibility between initial injection rate shaping and rapid closing on a common-rail fuel injector was discussed. As a result, common-rail injectors with a “variable inlet orifice” concept have better compatibility.