The invention discloses a method for treating chlorinated organic pollutants in underground water by using a slow-release compound repair material. The method comprises the following steps: (1), preparing charcoal through high temperature pyrolysis; (2), pre-treating zero-valent iron through acid pickling; (3), adding water into the charcoal, then adding xanthan gum and an organic carbon source, and finally, adding zero-valent iron, and through steps of treating, obtaining the slow-release compound repair material; then treating chlorinated organic pollutants in underground water by adopting an in situ injection repairing method or an in situ PRB repairing method. According to the method provided by the invention, the xanthan gum with high mechanical strength and strong mass transfer performance is used as a novel slow release embedding medium, the physical adsorbent charcoal, the chemical reductant zero-valent iron and the bioreductive drug organic carbon source are taken as effective components for composite embedding, so that gel microspheres with stable structures are formed, and the method provided by the invention has the advantages of sustained release, simple and convenient operation, low cost, environment friendliness and the like, can effectively achieve physically, chemically and biologically collaborated and enhanced remediation, and can effectively remove target pollutants.