To prevent coal mine disasters, it is not only necessary to predict the height of Water Conducting Fracture Zones (WCFZ), but also to grasp the development law of the WCFZ in time and space. Therefore, taking a working face as background, a similar simulation experiment was carried out using fiber optic sensing. Both five vertical optical fibers were evenly laid between the open-off cut and the stopping line, and four horizontal optical fibers with different heights were laid in the experiment model to characterize the spatiotemporal development of the WCFZ by the strain distribution variation. The results showed the optical fibers strain varies in a boss curve, the upper boundary of the boss in each vertical optical fiber keeps moving upwards while the right boundary of each horizontal fiber continuously shifts to the right, WCFZ presents an unequal trapezoidal shape development process. In this experiment, the height of the caving zone and WCFZ are 25.77m and 90.27m, the initial and final caving angle are 63°and 47.75°respectively. These results are consistence with those of Close-Range Photogrammetry and empirical formula. So, it is feasible to characterize WCFZ development by the horizontal and vertical optical fibers strain.