A financial restatement indicates low quality and affects the credibility of restating a company s financial statements. It brings not only serious economic consequences to the restating company， but also affects adversely companies in the group under same control. Using data of A listed firms from 2003 to 2014， we compare the market reaction of restating company and companies under same control before and after the restatement. We find that financial restatements in group companies has a negative contagion effect，and this effect will be influenced by the content of the restatement，the later period of the announcement，the auditor and the audit firms scale， the control of the enterprise group and the way of audit.