With the rapid development of voice call roaming, expanding in the areas of clearing, ensuring data availability and business continuity at the time of major accidents, natural disasters and other emergencies occurring is particularly important. According to the requirement and the problem needed to be improved of voice call roaming system, this paper thoroughly researches and analyses CDP disaster tolerant technology, proposes the method of applying the CDP technology to disaster tolerant system for voice call roaming clearing, designs and constructs the disaster tolerant system for Voice Call Roaming Clearing with continuous data protection and overalls data recovery. Practice has proved that this method can effectively protect data integrity and business continuity for voice roaming clearing systems in a variety of disaster scenarios.