This study initially identifies ten primary financial indexes, which are adapted from foreign insurance regulation system and relevant empirical research to be applicable for the property and casualty insurance industry in Taiwan, to estimate the ratio of unusual range of Taiwan's property and casualty insurers. The ten financial indexes are used to recognize the insurers which are in week or unhealthy financial status. The empirical results indicate that Kuohua and Taiping property and casualty insurance companies have been in the unusual range notably since 1997. This study further verifies the reliability of these indexes via comparing with the other financial health indexes using robust analysis. This study will provide Taiwan's property and casualty insurers and supervision institutions with references in early detecting their financial conditions and thus enhancing financial health via appropriate management and regulations.