We present a novel method for predominant vocal pitch detection in two-channel polyphonic music. The proposed method contains two stages. In the first stage, we apply the Frequency Domain Independent Component Analysis (FD-ICA) for the two-channel polyphonic music to separate the vocal content from the background music. Considering the vocal singing voice and background music are two heterogeneous signals, we employ a statistical learning based method to solve the permutation inconsistency problem in FD-ICA. In the second stage, a noise insensitive vocal pitch detection method is proposed, which is robust to noise and errors introduced by the separation process in the first stage. The proposed method has been tested on the two-channel polyphonic music signals, and experimental results show promising performance.