The hybrid analog and digital structure of large-scale antenna array offers a good tradeoff between cost and flexibility, which is a promising solution for millimeter-wave (mm-wave) system. This letter proposes a novel hybrid precoder (HP) design with an iterative beam split and detection algorithm, which works well for sparse mm-wave channels. The proposed strategy can extract the dominant propagation paths by iterative trainings, where the number of dominant paths up to that of radio frequency chains can be detected. The effectiveness and time overhead parameterized by the number of iterations are investigated. The experimental results demonstrated that we can approach optimal HP design with the proposed algorithm with only eight iterations for measured channels, which significantly reduced the complexity compared to the exhaustive search method.