The invention discloses a rod control and rod position system for a nuclear power station and a fault diagnosis method of the rod control and rod position system, and relates to the technical field of nuclear power. The rod control and rod position system for the nuclear power station comprises a control rod assembly, a rod control subsystem and a rod position subsystem, and further comprises a detecting subsystem, wherein the control rod assembly is used for controlling reaction of a nuclear reactor; the rod control subsystem comprises a control rod driving mechanism for driving the control rod assembly; the rod position subsystem is used for conducting measurement on a control rod of the control rod assembly to generate rod position information; the detecting subsystem is connected with the rod control subsystem and the rod position subsystem, is used for detecting the working current of the control rod driving mechanism in real time, and is used for diagnosing faults of the rod control subsystem. Through the arrangement of the detecting subsystem, a user or machine can obtain the fault information of the control rod driving mechanism in time.