Signal capture is one of the hot spots in electronic test. As the representative of testing instrument, the signal capture ability of digital oscilloscope is normally judged by the waveform capture rate. Unilaterally improving signal acquisition ability whereas ignoring the improvement of waveform imaging mechanism and display effect can not increase the oscilloscopes waveform capture rate in real sense. Aiming at better ability of signal acquisition and waveform display effect of oscilloscope, this paper is committed to analyzing the improved structure of oscilloscope and conducting the real-time waveform imaging with hardware coprocessor array, and then studying the imaging mechanism of special 3D waveform and the impact of waveform display on waveform capture rate. In this way, the signal capture ability of oscilloscope is greatly improved and the effective waveform capture rate as high as 1,000,000 wfms/s is realized.