The purpose of occurrence notification obligation is to enable the insurers to process investigation and save the evidence. Based on the specificity of Liability Insurance, there is often an interval of time between ”the accident which could give rise to insured's responsibility vis-à-vis a third party” and ”the time of a claim is asserted against the insured”. By comparing the basic liability insurance clause in Taiwan with the practice in common law, this paper found that there are some defects in the notification obligation in law and in contract in Taiwan; thus making recommendation on how to resolve these defects.