No matter in U.S.A or Taiwan, auto insurance business which is the main type of insurance in the property and casualty industry is the most primary part of property insurance. In all states, personal auto insurance policies are based on the terms of ISO personal auto insurance policies, while Taiwan personal auto insurance policies are based on the model contract for personal auto insurance. The study introduces the auto insurance system, structure and market operation overview of U.S.A and Taiwan, and then compares liability coverage, coverage for damage to your auto and other coverages, including medical payments coverage, uninsured motorrists coverage and theft loss coverage, and then compares conditional items, including general conditional items and claim conditional items, and finally compares additional terms. The study expects to provide complete protection for consumers of personal auto insurance in Taiwan by comparing those of the two countries.