A nitrogen-vacancy center based scanning magnetic microscope can be used to characterize magnetics at the nanoscale with high sensitivity. This paper reports a field-programmable-gate-array based hardware system that is designed to realize control and signal readout for fast scanning magnetic imaging with a nitrogen-vacancy center. A 10-channel 1 Msps @ 20 bit analog signal generator, a 12-channel 50 ps resolution pulse generator, a 300 Msps @ 16 bit lock-in amplifier with proportional integral derivative control function, and a 4-channel 200 Msps counter are integrated on the platform. A customized acceleration algorithm is realized with the re-configurable field-programmable-gate-array chip to accelerate the imaging speed of the nitrogen-vacancy system, and the experimental results prove that the imaging efficiency can be accelerated by five times compared to the system without the acceleration algorithm. The platform has considerable potential for future applications of fast scanning magnetic imaging.