Abstract: Withrapid development of selective laser melting (SLM) Technology, demand for SLM equipments used in forming large complex metal parts has increased. Form of structure of the equipment should be decided on considering both handling large metal part and its substrate and process characteristics of SLM technology. This article expounded design thought for an selective laser melting equipment of large metal parts, and put forward its structure scheme, and described its components and key points of design.