CAR-T therapy is a novel therapy to treat tumors. It has realized the precise treatment of tumors by transforming the modified CAR gene into patients’ self T cells, driving the T cells expressing specific antibodies which are able to bind surface antigens to tumors. CAR-T has been in its fourth generation since put forward. This therapy exists both certain effects and risks in blood tumors as well as solid tumors but exposes some difficulty waited to be solved. In this review, we describe the treatment and existing problems of CAR-T therapy in blood tumors and solid tumors.