Rapid developments and wide applications of optical coherence tomography (OCT) have been achieved since its first coming into being. Doppler OCT is an important functional extension of existing OCT imaging modality. Spectral domain OCT (SD-OCT) system and its applications in dynamic monitoring of blood flow in a rat brain model and three-dimensional flow-field measurement of a microfluidic chip are presented. Recent advances in Doppler imaging method and system developments are reported, including sensitive phase retrieval for Doppler imaging through higher-order cross-correlation, vector-velocity quantification by two-zone beam divider and transit-time analysis, ultralong-range orthogonal dispersive SD-OCT system and its application in phase-sensitive imaging.