Abstract: A fault detection method comprises the following steps. Receiving a first original sequence comprising a plurality of first data. Receiving a second original sequence comprising a plurality of second data. Aligning the first original sequence with the second original sequence according to trends of value changing of the first data and the second data. Performing an average operation on the aligned first original sequence and second original sequence to establish a standard sequence. Performing a difference operation between the first original sequence and the standard sequence to obtain a first total difference value. Performing a difference operation between the second original sequence and the standard sequence to obtain a second total difference value. When the first total difference value and/or the second total difference value is greater than an upper limit value, determining that the first original sequence and/or the second total difference value is abnormal.