As the fourth-generation wide bandgap semiconductor, diamond is increasingly used in the nuclear field, especially single-crystal chemical vapor deposition (scCVD) diamond, due to its radiation resistance and stable chemical properties. Applications include reactor operation monitoring and detection of reaction products in nuclear fusion. In these complex radiation fields, gamma rays, neutrons, and other charged particles deposit energy into the diamond and generate pulse signals. Different types of radiation undergo different physical processes in scCVD diamond, resulting in different signal pulse shapes. Previous research report that the pulse signals of gamma rays in diamond are triangular, the signals of neutrons are step-shaped and rectangular, and the signals of alpha particles are rectangular. In this paper, we develop a scCVD diamond-based detector system capable of real-time measurements. The detector system includes a current preamplifier circuit with pulse-shape discrimination capability, a signal acquisition system, and a host computer display system. The detector system successfully collects gamma signals from the 137Cs and 60Co sources, alpha signals from the 241Am source, and D–T neutron signals. The energy calibration of the scCVD diamond detector through 12C(n,α)9 Be reaction. Then, we obtain the energy spectra of D–T neutrons and 137Cs and 60Co gamma rays. Finally, Though Geant4 simulation to obtain the energy deposition spectra of these rays in diamond. The simulation results are basically consistent with the experimental results. (Potential application) In the future work, we plan to implement neutron and gamma signal discrimination. This scCVD diamond detector system is expected to be used for gamma and neutron dose measurement in mixed radiation fields, such as BNCT radiation fields.