The invention discloses beta-carboline derivatives with HDAC (histone deacetylase) inhibitory activity as well as a preparation method and an application thereof. A product is a compound with the general formula (I); the beta-carboline derivatives with the HDAC inhibitory activity can be used as cancer drugs for treating and/or preventing liver cancer, colon cancer, pancreatic cancer, breast cancer, lung cancer, ovarian cancer, bladder cancer and gastric cancer.