Provided are a siRNA of the human interleukin 6, a recombinant expression CAR-T vector, and a construction method and a use thereof. The siRNA can be used in the treatment of acute B-cell lymphocytic leukemia with CAR19-T for eliminating or alleviating the symptoms of cytokine release syndrome (CRS), and can also be used for alleviating the CRS symptoms caused by treating tumours with CAR-T and even can also be used for alleviating CRS caused by other types of treatment.