There are more and more accidents in the chemical plants due to high risk state and difficult safety management, such as unplanned shutdown, serious leakage of toxic and harmful chemicals, fire and explosion, and so on. These accidents have a huge negative impact on the society, economy, and environment. Accident causation model is an important technique for accident scenario construction and deduction; however, those traditional models cannot fully capture the dynamic and nonlinear interaction between system elements, or precisely stick to the cause analysis of system element errors and effective development of elimination measures. Therefore, the functional resonance analysis method (FRAM) was introduced to deduce the potential accident scenario of chemical plants from a perspective of systematical function features. There were four major procedures in the FRAM, including the identification and description of basic functions, the performance change assessment of every function, the possibility determination of functional resonance, and the response measure development of performance change. To illustrate its validity, the BP Texas City refinery explosion was selected as a test case in this work. Particularly, each functional performance change and functional failure connection of the raffinate section were clearly illustrated in the functional network diagram. It mainly involved the raffinate splitter tower, heating furnace, heat exchanger, blowdown drum and stack, different kinds of instruments, as well as operators. Results from the above-mentioned accident showed that this method was competent to deeply trace the accident occurrence process and evolution scenario, which could be further applied to reveal the cause mechanism of chemical plant accidents and excavate the weak points of chemical plants. Moreover, the FRAM was also compared with two other traditional methods-sequentially timed events plotting (STEP) and accident map (AcciMap). In summary, the introduced FRAM was verified to be feasible, effective, and reasonable for the accident scenario deduction of chemical plants.