The strong effective magnetic fields with flux to the order of one flux quantum per plaquette has been realized for ultracold atoms,and the quantum cyclotron orbit of a single atom in a single plaquette exposed to the magnetic field was directly revealed recently [Phys.Rev.Lett.107 (2011) 255301].We study the quantum cyclotron orbits of a bosonic atom in a triple well with a synthetic gauge field,and find that the dynamics of the atom in real space is similar to a classical dynamic billiard.It is interesting that the billiard-like motion is a signature of the quantum evolution of the three-level system,and its behaviors are determined by the ratio of the two energy gaps of the three energy levels.