Chirality has played a critical role in studying optical activity, multiferroics, and superfluidity. This talk concerns a scattering problem with obliquely incident electromagnetic waves in a chiral medium. The left-circular polarization and right-circular polarization are used, and the model problem is reduced to a coupled boundary value problem of the Helmholtz equations. The potential operators are investigated to establish coupled boundary integral equations. The operators' properties are obtained in Sobolev spaces by splitting techniques to overcome the singularity of integral operators. Then we prove the existence and uniqueness results for the integral equations and develop an efficient and accurate method to solve the coupled system. Numerical experiments are presented to demonstrate the effectiveness and robustness of the proposed methods.