A method of detecting surface pressure distribution of a wafer being processed by a CMP (Chemical Mechanical Polishing) process; more specifically, the invention relates to a method of detecting pressure distribution of a wafer surface by employing pressure sensitive films located on various pressure components such as a wafer carrier, a polishing pad, and mechanical arm members of a CMP machine for detecting pressure-related data during different stages of a CMP process. Further, sensed pressure-related data are collected for feedback loop controls of digital image mapping, numeration, simulation, and forecasting, from which more mechanical components of high precision and better circuit layouts on the wafer can then be developed.