& Optical fiber sensors have been applied for process tomography of gas=liquid and gas=solid two-phase flow systems, such as hydraulic flow rig, pneumatic conveying, fluidized beds, and flame combustion. Optical fiber process tomography has the general characteristics of non-invasiveness, high accuracy, and security. For optical fiber image reconstruction of rate and accuracy, a large number of scholars have been active in this area in recent years. This article systematically and thoroughly describes optical fiber sensors in process tomography applications, for instance, hardware components, optical structure, and the reconstruction algorithm. With the research going on, the technology of optical fiber sensors will be more significant in process tomography and other fields.