This paper presents a USB 3.0 based readout platform for real-time ion imaging applications. The front end utilizes an ion-imaging array containing 16 k ISFET pixels to capture ion diffusion at ~6100 fps. Operating at 200MHz, the chip streams ion information at a data rate of ~95 MB/s. The backend readout system employs a FIFO-to-USB bridge (FT601Q) that supports Super Speed (5Gbps) to perform real-time data streaming and operates in bulk transfer mode to ensure data integrity. Implemented on a Xilinx Virtex UltraScale+ FPGA, the system involves a high-throughput data path through the onboard DDR4 SDRAM, in which a ring buffer is also designed to provide the 2GB buffering capacity. The readout system can operate in real time regardless of the USB glitches encountered on the Windows OS when involving data polling. In addition, a simple differencing algorithm with threshold detection is integrated into the back end for dynamic frame rate operation. The proposed readout system performs real-time ion imaging at high speed as well as streams the collected images for visualization within a latency of 25 ms, achieving state-of-the-art performance for high-speed Lab-on-Chip applications.