For the first time, a new probe for fast ion loss has been developed for use in the Experimental Advanced Superconducting Tokamak (EAST) and utilizes optical fiber transmission, the aim of the probe is to study fast ion losses triggered by the ion cyclotron range of frequencies (ICRF) heating and neutral beam injection (NBI) synergy. This probe is used to determine the pitch angle and gyroradii of the ion losses based on the particle positions striking the two-dimensional scintillator. In this paper, the calculation and design of the probe scintillator by using the NLSDETSIM code is discussed. The emitted light from the scintillator is captured by a high-speed camera via an optical lens and high-temperature-resistant fibers and then processed by a signal processing system to determine the real-time energy and angle of the fast ion. Due to the flexible nature of the fiber, the probe is capable of measuring the fast ion losses at various locations within the EAST. Furthermore, the probe can be easily installed by using one of the numerous vacuum feeds on the EAST instead of occupying the entire window. This feature enhances the flexibility of the diagnostic technique.