The present invention relates to a novel hexahydrodibenzo[a,g]quinoline compound represented by general formula (I) and its derivatives, enantiomer, diastereoisomer, raceme and mixtures thereof, as well as pharmaceutically acceptable salts thereof. The present invention further relates to a method for preparing the compound, and the compound has good prevention and treatment effect on neurological diseases, especially diseases associated with dopamine receptor and 5-hydroxytryptamine receptor. The bioactivity experiment demonstrates that, the compound is expected to be developed into a novel and potent chemical entity for treating diseases associated with dopamine receptor and 5-hydroxytryptamine receptor, especially schizophrenia, Parkinson's disease, drug addiction, migraine and so on.