This paper took Support Object System as the research object. With defining the basic concepts just like combat unit, it constructed the three-dimension researching framework of RM modeling for support object system using System Engineering theory, from parameter, time domain and hierarchical these three aspects. It established the RM parameter system for the smallest combat unit -Basic Equipment Combat Unit’s support object system, with distinguishing the comprehensive and monomial parameters. Operational mission-oriented RM model of baisc equipment combat unit was established subsequently, with multiple modeling theories and methods, such as phased-mission system and reliability block diagram, etc. This model could provide the foundation for operational mission-oriented support resource deployment and support efficiency evaluation.