An ocean state monitor and analysis radar(OSMAR), developed by Wuhan University in China, have been mounted at six stations along the coasts of East China Sea(ECS) to measure velocities(currents, waves and winds) at the sea surface. Radar-observed surface current is taken as an example to illustrate the operational high-frequency(HF) radar observing and data service platform(OP), presenting an operational flow from data observing, transmitting, processing, visualizing, to end-user service. Three layers(systems): radar observing system(ROS), data service system(DSS) and visualization service system(VSS), as well as the data flow within the platform are introduced. Surface velocities observed at stations are synthesized at the radar data receiving and preprocessing center of the ROS, and transmitted to the DSS, in which the data processing and quality control(QC) are conducted. Users are allowed to browse the processed data on the portal of the DSS, and access to those data files. The VSS aims to better show the data products by displaying the information on a visual globe. By utilizing the OP, the surface currents in East China Sea are monitored, and hourly and seasonal variabilities of them are investigated. An ocean state monitor and analysis radar (OSMAR), developed by Wuhan University in China, have been mounted at six stations along the coasts of East China Sea (ECS) to measure velocities (currents, waves and winds) at the sea surface. Radar -observed surface current is taken as an example to illustrate the operational high-frequency (HF) radar observing and data service platform (OP), presenting an operational flow from data observing, transmitting, processing, visualizing, to end-user service. Three layers (systems): radar observing system (ROS), data service system (DSS) and visualization service system (VSS), as well as the data flow within the platform are introduced. Surface velocities observed at stations are synthesized at the radar data receiving and preprocessing center of the ROS, and transmitted to the DSS, in which the data processing and quality control (QC) are conducted. VS S aims to better show the data products by displaying the information on a visual globe. By utilizing the OP, the surface currents in East China Sea are monitored, and hourly and seasonal variabilities of them are investigated.