The big data analytics platform is an indispensable infrastructure for big data processing and applications. Based on our research activities, practical experiences with big data analytics, and lessons learnt from industrial projects, this paper addressed the platform design, mainstream technologies, and industrial cases of big data analytics platforms. Firstly, the main functions and architecture of such platforms were analyzed. Then the key enabling technologies were introduced with a focus on the architecture of Spark and its core components. Finally three application case studies were presented in the areas of massive manufacture, retail, and smart grids.