The Blowout Accident had occurred at 20th April, 2010 in the Gulf of Mexico which included the 11 lives were lost. After that, it was caused the extensive oil spill and serious marine pollution in the coast area. The water depth of well M is 4,992ft and the accident has happened during the temporary abandonment operation after the production casing setting at the 13,000ft below the seabed. This paper describes the technical outline of the accident and analyzes by the collected information which includes issues, questions and unique interpretations. From the aspects of the accident summaries, we suggest the considerations for the future deepwater drilling technology.