To meet the requirements of multichannel fluorescence correlation spectroscopy with a wide dynamic range, a digital correlator based on field programmable gate array (FPGA) technology was designed and implemented. The hardware structure was designed and implemented using a register-level hardware description language. Based on the characteristics of photon pulse counting signals, the multi sampling time correlation and time-division multiplexing methods were used to calculate the correlation function, which substantially improved computing efficiency and optimized hardware resource utilization. The time-division multiplexing of cross correlation was extended to triple correlation, and the corresponding method was extended to adapt triple correlation. Ultimately, a real-time computing triple correlator based on FPGA was realized. The calculation method of symmetric normalization ensured the accuracy of the correlation function. The designed photon correlator was implemented based on a single Xilinx Zynq-7100 FPGA chip, which performed various functions, including the real-time correlation of three channels auto-correlation, three channels cross-correlation, and one channel triple correlation, with the time resolution of 40 ns and dynamic range of 1.57 × 10⁷.