A fault detection method for a refrigeration system, comprising: an initial detection step, wherein the initial detection step comprises: acquiring an output current or output power of a power source when system parameters are stable; and when the system parameters are unstable, re-determining whether the system parameters are stable after a delay of first predetermined time; calculating a theoretical output current or output power of the power source; comparing the output current or output power of the power source with the theoretical output current or output power of the power source to determine whether an anomaly exists in the system; and marking a system anomaly if an anomaly exists in the system; and a fine detection step, wherein the fine detection step comprises: determining whether there is a system anomaly mark, wherein if there is no system anomaly mark, the method returns to the initial detection step; re-determining whether the system parameters are stable, wherein if the system parameters are unstable the fine detection step is started again after a delay of a certain time; and changing a working state of at least one device (5, 6, 7, 8), and comparing the output currents or output powers of the power source before and after the working state of the at least one device is changed, so as to determine whether an anomaly exists in the at least one device. an initial detection step, wherein the initial detection step comprises: acquiring an output current or output power of a power source when system parameters are stable; and when the system parameters are unstable, re-determining whether the system parameters are stable after a delay of first predetermined time; calculating a theoretical output current or output power of the power source; comparing the output current or output power of the power source with the theoretical output current or output power of the power source to determine whether an anomaly exists in the system; and marking a system anomaly if an anomaly exists in the system; and acquiring an output current or output power of a power source when system parameters are stable; and when the system parameters are unstable, re-determining whether the system parameters are stable after a delay of first predetermined time; calculating a theoretical output current or output power of the power source; comparing the output current or output power of the power source with the theoretical output current or output power of the power source to determine whether an anomaly exists in the system; and marking a system anomaly if an anomaly exists in the system; and a fine detection step, wherein the fine detection step comprises: determining whether there is a system anomaly mark, wherein if there is no system anomaly mark, the method returns to the initial detection step; re-determining whether the system parameters are stable, wherein if the system parameters are unstable the fine detection step is started again after a delay of a certain time; and changing a working state of at least one device (5, 6, 7, 8), and comparing the output currents or output powers of the power source before and after the working state of the at least one device is changed, so as to determine whether an anomaly exists in the at least one device. determining whether there is a system anomaly mark, wherein if there is no system anomaly mark, the method returns to the initial detection step; re-determining whether the system parameters are stable, wherein if the system parameters are unstable the fine detection step is started again after a delay of a certain time; and changing a working state of at least one device (5, 6, 7, 8), and comparing the output currents or output powers of the power source before and after the working state of the at least one device is changed, so as to determine whether an anomaly exists in the at least one device.