Shark attacks can make beach tourists anxious about sharing the ocean with apex predators. Although the raw number of shark attacks is deficient, the absolute terror caused by sharks is genuine. This paper introduces a novel method named as 'drone shark shield system', which uses communicating autonomous drones to intervene and prevent shark attacks for protecting swimmers and surfers. We detail the design of the drone shark shield system and the strategy for repelling sharks through multiple intersections. A shark interception algorithm is developed to guide drones to predicted intersection points for deterring sharks. Computer simulations are conducted to illustrate our method.