A virtual platform is developed to support the design of tunnel drilling rigs, which is used to drill holes in underground coalseam for gas drainage. Firstly, a three-layer framework of virtual platform is established, which includes the base layer, platform layer, and application layer to provide data, information and techniques respectively. A virtual design flow of drilling rigs is subsequently defined. Then three key techniques for the virtual design of drilling rigs is proposed, which are digital modelling, digital simulation and digital management. The first is used to support 3-D modelling, the second is used to analyze the dynamic performance, and the third is to manage the design data. Finally, a design case of ZDY6000LDA drilling rig is given to demonstrate the application of this platform.