Optical coherence tomography (OCT) can image the structure of the biological samples with high resolution and non-destruction. By analyzing the phase or intensity change of the signal, we can distinguish the motion tissue and the static tissue in the sampler, and then extract flow fieldfield information. Various methods are summarized to detect blood flow in blood vessel. OCT has become a powerful tool for the clinical measurement of vascular microcirculation, since it can image blood vessel in skin or retina without any auxiliary reagent. We reviewed six typical methods in Fourier OCT: phase-resolved Doppler OCT, phase-resolved Doppler variance, intensity-based Doppler variance, speckle variance, split-spectrum amplitude-decorrelation angiography, and optical micro-angiography. Each method has its own advantages and disadvantages on phase stabilization, flow rate measurement, signal-to-noise ratio, and real time. Imaging schemes are optimized based on the six methods. Finally, the prospects of OCT are included.