Warm welcome to the official website of 2025 9th International Conference on Big Data and Internet of Things (BDIOT2025). The Conference will be held in Chongqing, China during November 7-9, 2025. BDIOT2025 is sponsored by Chongqing Technology and Business University (CTBU), China. The rapid advancement and ubiquitous penetration of mobile network, web based information creation and sharing, and software defined networking technology have been enabling sensing, predicting and controlling of physical world with information technology. Every business process can be empowered, and therefore, various industries redesign their business models and processes along Internet of Things (IoT) paradigm. The main purpose of BDIOT2025 is to provide an international platform for presenting and publishing the latest scientific research outcomes related to the topics of Big Data and Internet of Things.