The utility model provides a state monitoring and fault diagnostic of reciprocating type equipment, wherein, the system includes: observe and control subsystem, base, and set up driven element system on the base, power train subsystem, by driver part subsystem, load excitation subsystem, trouble realization subsystem and variable working condition realization subsystem. Wherein, the driven element system, passed through power train subsystem coaxial mechanical connection in proper order by driver part subsystem and load excitation subsystem, the trouble realize the subsystem with by driver part subsystem mechanical connection, the variable working condition realizes subsystem and trouble realization subsystem mechanical connection, observe and control the subsystem respectively with the driven element system, realized sub - system electric connection by driver part subsystem, load excitation subsystem and variable working condition. The utility model discloses can reappear the running state with the high degree of approximation of big -and -middle -sized reciprocating type equipment, can produce less monitoring error and higher diagnosis precision in state monitoring and failure diagnosis in -process.