Since pioneering work in 1972, the proportional hazard model (PHM) has been widely studied for survival analysis in the area of medicine. Recently, applying the PHM in the area of reliability engineering attracts significant research attentions. In this paper, a two-zone PHM is investigated to predict equipment remaining useful life (RUL) based on the practice that the equipment lifecycle could be divided into two zones: a stable zone and a degradation zone. Results from the numerical experiment illustrate that RUL prediction by applying the proposed two-zone PHM is more accurate and reliable than prediction using the traditional PHM for the entire lifecycle. In practice, this improvement is crucial for real-time maintenance decision making to prevent equipment from catastrophic failures.