The present invention relates to a nitrogen heterocyclic derivative, a preparation method therefor, and a pharmaceutical use thereof. In particular, the present invention relates to a nitrogen heterocyclic derivative represented by the general formula (I), a preparation method therefor, a pharmaceutical composition containing the same, and a use thereof as an SMO antagonist, particularly in the treatment of Hedgehog signaling pathway-associated diseases such as cancer. The definitions of the groups in the general formula (I) are the same as those in the specification.