The High Energy cosmic-Radiation Detection (HERD) facility has been proposed as one of several space astronomy payloads onboard the future China's Space Station, planned for operation starting around 2025 for about 10 years. HERD is a China-led mission with key European contribution led by Italy. The HERD proposal has passed the joint international review organized by the Italian Space Agency and the Center for Space Utilization of the Chinese Academy of Science. The primary scientific objectives of HERD are: Indirect dark matter search with unprecedented sensitivity; precise cosmic ray spectrum and composition measurements up to the knee energy; Gamma-ray monitoring and full sky survey. HERD is composed of 4 scientific instruments. The main one is a homogeneous, almost cubic calorimeter made of about 7500 LYSO cubic crystals and capable of accepting particles incident on its top face and four lateral faces. Each sensitive face is instrumented with a silicon tracker, and covered by a plastic scintillator detector to separate gamma rays from charged particles. Additionally, a transition radiation detector is located on one lateral face for energy calibration of TeV particles. This design results in an effective geometric factor more than one order of magnitude larger than that of previous missions, and also excellent lepton/hadron separation capabilities thanks to the 3D nature of the calorimeter. The novel design and key specifications of HERD instruments have been successfully verified with beam tests at the CERN SPS.