Abstract: The aerodynamic ambient flow around parallel cables in a cable-stayed bridge under natural wind has obvious three-dimensional features, which are different from the horizontal ideal parallel cylinders. With parallel cables in a real bridge regarded as an engineering example, a set of experimental rigs and the corresponding test methods in wind tunnel are developed to investigate the wake galloping of parallel cables. With focus on the phenomenon of wake galloping in a large spacing instability range, a series of wind tunnel tests were carried out. The characteristics of the track of the model cables are discussed when wake galloping occurs in the wind tunnel. The effect of cables distance, wind yaw angle and wind attack angle on the vibration of downstream cables is compared and analyzed respectively. The conclusions can direct the wind-resistant design of the cables in cable-stayed bridges.