The present invention provides a method for 3D waveform mapping of full-parallel structure, first, a 3D waveform mapping database is created according to the size of a 3D waveform image, the number of bits of probability value and the ADC's resolution of data acquisition module, then the 3D waveform mapping database is divided into Mt×Ma independent mapping storage areas along the time axis and the amplitude axis, and each independent mapping storage area is assigned a RAM, then RAMs are selected and addresses are calculated based on the sampling values and the structure of created 3D waveform mapping database, finally, parallel mappings are performed simultaneously on the time axis and the amplitude axis according to the selected RAMs and calculated addresses. Thus, the mapping time are shorten, especially in vector mapping mode, several RAMs are used for mapping, so the WCR of DSO is improved.