A refrigerator detecting an abnormal state, comprising: a temperature sensor configured to sense a temperature of a refrigerating compartment and a freezer compartment; a door sensor configured to sense an opening and closing of a door; a sensor of a compressor configured to sense an operation pattern of the compressor; an ice sensor configured to sense an amount of ice used and a state of generated ice; a water quantity and water pressure sensor configured to sense an amount of water used and water pressure; a defrost sensor configured to sense frost generated in the refrigerator; a storage unit configured to store information sensed by the sensors in combination with time information; a communication unit configured to transmit the stored information and setting information set for the refrigerating compartment and the freezer compartment to a cloud server; a display unit configured to output information; and a controller configured to control the sensors, the storage unit, the communication unit, and the display unit, and when the communication unit receives information on an abnormal state of the refrigerator generated by the cloud server or a monitoring server based on the sensing information sensed by the sensors, the controller configured to control the display unit to output the received information on the abnormal state, characterized in that the information on the abnormal state is generated by the cloud server based on first sensing information and second sensing information having an association with each other among the sensing information sensed by the various sensors, and wherein the association denotes the second sensing information generated by a specific sensor being not matched with pattern information stored in the cloud server, and the cloud server determines a state of the second sensing information that does not match with the pattern information as an abnormal state based on the first sensing information generated by other sensors different from the specific sensor, and generates the information on the abnormal state. a temperature sensor configured to sense a temperature of a refrigerating compartment and a freezer compartment; a door sensor configured to sense an opening and closing of a door; a sensor of a compressor configured to sense an operation pattern of the compressor; an ice sensor configured to sense an amount of ice used and a state of generated ice; a water quantity and water pressure sensor configured to sense an amount of water used and water pressure; a defrost sensor configured to sense frost generated in the refrigerator; a storage unit configured to store information sensed by the sensors in combination with time information; a communication unit configured to transmit the stored information and setting information set for the refrigerating compartment and the freezer compartment to a cloud server; a display unit configured to output information; and a controller configured to control the sensors, the storage unit, the communication unit, and the display unit, and when the communication unit receives information on an abnormal state of the refrigerator generated by the cloud server or a monitoring server based on the sensing information sensed by the sensors, the controller configured to control the display unit to output the received information on the abnormal state, characterized in that the information on the abnormal state is generated by the cloud server based on first sensing information and second sensing information having an association with each other among the sensing information sensed by the various sensors, and wherein the association denotes the second sensing information generated by a specific sensor being not matched with pattern information stored in the cloud server, and the cloud server determines a state of the second sensing information that does not match with the pattern information as an abnormal state based on the first sensing information generated by other sensors different from the specific sensor, and generates the information on the abnormal state.