The application of three-dimensional mapping technology has improved the waveform capture rate of digital storage oscilloscopes(DSO), however it does not eliminate the dead time of DSO. In this research, a new 3D-imaging method, fragmentation and centralized mapping, is proposed. It divides high-speed large capacity dynamic memory(DDR3 SDRAM) into several regions based on the time-base. In each region, the waveforms with the same triggering condition are stored, and the waveforms will be post-processed with three-dimensional mapping Technology. Dual-port RAM based fast waveform mapping technology and parallel waveform mapping technology decrease the mapping time greatly. This method guarantees high waveform capture rate and enable larger data storage capacity. It also enables seamless acquisition for the duration of each stored waveform. By mathematical modeling, it can be proven that our system can capture the sporadic transient event in shorter time. Through double pulse test method, it can be demonstrated that the highest capture rate of the system is measured to be 6 250 000 wfms/s. After analysis, it is obtained that the ratio of dead time is reduced to 43.86%.