With the development of nuclear physics technology, traditional electronic modules are no longer able to meet the increasingly demanding requirements of nuclear physics experiments. Digital instruments have been widely used due to advantages of high integration and flexible data processing. We attempt to use the Pixie-Net digitizer for the γ-γ coincidence experiment using the NaI and CeBr3 detectors in order to simplify experimental equipment and to improve teaching effectiveness. The results show that after optimizing the parameters of the digitizer based on the pulse shapes and correcting the difference in angular correlation coefficient caused by the size of the detector and radiation source, the activity error of the radioactive source between the test value and the theoretical value is less than that from the β-γ coincidence method based on traditional electronics.