This paper introduces a design of digital fluxmeter based on FPGA. The sequence of synchronous ADC is controlled by FPGA sampling at a fixed frequency. Some functions have been realized using the FPGA such as digital filtering, automatic calibration, automatic range selection and digital integral. Compared with analog fluxmeter, the design simplifies the operation of instrument and improves system stability. The experiment indicates that the accuracy of the digital fluxmeter can reach the range of less than 0.5% with zero drift.