For the purpose of technological analysis in the marine accidents and their prevention, IMO have made it obligatory to load VDR which is similar to the black box in aircraft. However, in case of body sinkage, capsizing, stranding and plunging which are almost 10% of marine accidents, it is difficult to take out the necessary data from the VDR in order to analyze the cause of them. Therefore, this paper apply the navigation dangerousness evaluation technology to the VDR to improve its performance. And we suggest that the vertical acceleration which is one of the factors for evaluating seakeeping performance of a ship is to be added in the existing VDR record data recommended by IMO.