Disclosed are an abnormal state detecting apparatus of a multi-type air conditioner and a method thereof. The method comprises: a user's selecting a test operation, and then detecting plural indoor temperatures of indoor zones where a plurality of indoor units are installed and plural outdoor temperatures of outdoor zones where a plurality of outdoor units are installed; selecting a corresponding test operation mode among a plurality of test operation modes preset according to an average indoor temperature of the detected plural indoor temperatures and an average outdoor temperature of the detected plural outdoor temperatures; test-operating the multi-type air conditioner according to the selected test operation mode, and collecting data showing an operation state of the test-operated air conditioner; and comparing the collected data with a preset reference data and judging an abnormal state of the air conditioner based on the comparison result.