Successful implementation of construction projects depends on accurate cost estimation. Cost analysis of construction work items is essential to a cost estimating process for contractors. However, current cost analysis tasks cannot be implemented effectively in practices. Therefore, this study proposes an ontology-based representation framework that aims to address such practical problems. The framework can be used to establish a cost analysis knowledge base which can benefit the modeling and application of cost analysis knowledge and hence, improve the accuracy of cost analysis and estimation. This framework is developed by using the ontological modeling technique with which key cost items of cost analysis and relationships among these cost items can be modeled and subsequently be examined. Actual cost analysis information of eight cases were collected and used to demonstrate and validate the framework. The case study results show that the proposed representation framework can effectively model and store cost analysis knowledge from both historical data as well as current professional work. Furthermore, the modeled cost analysis knowledge can be reused in new cost analysis tasks, and the accuracy and efficiency of cost analysis and estimates can be improved by eliminating the possibility of leaving out necessary cost breakdown items. Future research is suggested on improving the framework by developing a reasoning mechanism that can automate cost analysis processes of reusing existing cost analysis knowledge.