As one of the key infrastructure, cost control of power engineering is crucial for economic benefits and sustainable development. With the development and application of Internet of Things technology, the cost management of power engineering has ushered in new opportunities and challenges. This article first analyzes the challenges and problems in current cost management of power engineering, including management weaknesses, difficulty in cost control, and information closure; Next, the basic concepts and development background of the Internet of Things were introduced, and the current situation of combining the cost of power engineering with the Internet of Things and big data; Then, taking the construction drawing budget as an example, analyze the weak points of construction drawing budget management, and combine the Internet of Things and big data technology to propose measures to strengthen the control of construction drawing budget; Finally, the future development trends of Internet of Things technology in cost control of power engineering were discussed. In summary, with the continuous innovation and application of technology, the role of the Internet of Things in cost control of power engineering will be further strengthened.