The invention belongs to the technical field of oil moisture content detection and relates to an online hydrocarbon moisture content and pure oil density analyzing skid system. The online hydrocarbonmoisture content and pure oil density analyzing skid system disclosed by the invention comprises a sampler arranged on a medium pipeline to be measured, a moisture content analyzing skid main body connected with the sampler and a data acquisition system, wherein the moisture content analyzing skid main body comprises a filtering device, a sampling pump, a density measuring device and a moisture content analyzer which are sequentially connected; the density measuring device and the moisture content analyzer are electrically connected with the data acquisition system. The system achieves online,real-time and high-efficiency monitoring on hydrocarbon moisture content and quality, reduces interference of manual factors and effects of oil component change on moisture content measurement, improves reliability and accuracy of measurement data, can obtain high-performance measurement value and can achieve industrial application easily.