This digital oscilloscope takes a MCU and FPGA as the core. We made emphases on the choice of the sampling methods and the implement of equivalent sampling as a result, our design not only has the real-time sampling mode but also can reach the highest equivalent sample rate of 200 MHz using the real-time sample rate of 1 MHz, by way of random equivalent sampling. At the same time, this system has many other functions, such as 2 mV small-signal measuring, storage and re-display of waveform, measuring frequency, selective trigger edge, output of the correction signal and so on.-This digital oscilloscope takes a MCU and FPGA as the core. We made emphases on the choice of the sampling methods and the implement of equivalent sampling　as a result, our design not only has the real-time sampling mode but also can reach the highest equivalent sample rate of 200 MHz using the real-time sample rate of 1 MHz, by way of random equivalent sampling. At the same time, this system has many other functions, such as 2 mV small-signal measuring, storage and re-display of waveform, measuring frequency, selective trigger edge, output of the correction signal and so on.