The document describes a project to develop a guideline-based clinical decision support system (CDSS) for COVID-19 using openEHR archetypes and the Guideline Definition Language (GDL). A team from Zhejiang University extracted diagnostic and treatment guidelines from Chinese sources and represented them in openEHR templates and GDL rules. Two CDS applications were implemented and are being deployed in hospitals to aid diagnosis and screening of COVID-19 patients. The project aims to demonstrate how open standards like openEHR can facilitate rapid development and sharing of computerized clinical guidelines.