Abstract：The approach to investigation and assessment of organic contaminants in regional groundwater is presented based on the practical conditions in China and by referring to the experience in regional groundwater contamination investigation of foreign countries. The approach includes selection of indices of organic contaminant investigation, selection and rinsing procedures of sampling wells, sample collection, preservation and transportation for detection, analytical methods and target detection limit, quality control of field sampling and analysis, assessment of organic contaminant detection and assessment of methods for assessment of organic contaminants in excess of standards and relevant analytical methods.