A multi-GPU system designed for high-speed, real-time signal processing of optical coherence tomography (OCT) is described herein. For the OCT data sampled in linear wave numbers, the maximum processing rates reached 2.95 MHz for 1024-OCT and 1.96 MHz for 2048-OCT. Data sampled using linear wavelengths were re-sampled using a time-domain interpolation method and zero-padding interpolation method to improve image quality. The maximum processing rates for 1024-OCT reached 2.16MHz for the time-domain method and 1.26MHz for the zero-padding method. The maximum processing rates for 2048-OCT reached 1.58 MHz, and 0.68MHz, respectively. This method is capable of high-speed, real-time processing for OCT systems.