A chain fault diagnosis system and a chain fault diagnosis method for a scraper conveyor are provided. The diagnosis system includes a strain rosette attached on a top end surface of each sprocket tooth of the scraper conveyor. The strain rosette is connected to a signal gathering unit fixed on a scraper conveyor roller through a shielded conductor, the signal gathering unit sends a gathered signal to a wireless receiving device by means of wireless transmission, and the wireless receiving device transmits the gathered signal obtained thereby to an industrial control computer through a USB interface. The diagnosis method includes the following three steps: chain dislocation/skip fault judgment, chain breakage fault judgment and chain seizure fault judgment. A comprehensive monitoring of the chain state of the scraper conveyor is performed by measuring strain magnitudes in different directions of the sprocket tooth in real-time, transmitting the gathered signal to the industrial control computer via a wireless transmission method and dynamically diagnosing the faults of seizure, dislocation, skip and breakage of the scraper conveyor chain based on the obtained strain data.