Objectives: Despite the great success of CD19 CAR‐T cell therapy, its clinical efficacy has been greatly hampered by the high relapse rate. In this study, we designed and compared four structures of CD19/CD22 bispecific CAR‐T cells with different linkers and different orders of the antibody sequences. Methods: We detected the cytotoxicity, cytokine secretion levels, sustainable killing ability, differentiation, exhaustion of these four CAR‐T cells in vitro. The optimal Bis‐C CAR‐T cells were evaluated the efficacy using NSG mice. Results: The two structures of CD19/CD22 bispecific CAR‐T cells using (EAAAK)3 as linker had more significant cytotoxicity and cytokine secretion levels. In the process of continuous killing, Bis‐C CAR‐T cells showed better sustained killing ability, memory phenotype differentiation, and exhaustion. In the in vivo experiment mimicking CD19‐negative relapse, Bis‐C CAR‐T was more able to control the tumor progression of mice in the CD19 low expression or no expression groups than CD19 CAR‐T. Conclusions: This study has generated a novel bispecific CAR‐T cell that can simultaneously target CD19 or CD22 positive tumor cells, providing a new strategy to address the limitations of single‐targeted CAR‐T therapy in B‐cell tumors (limited response or relapse). [ABSTRACT FROM AUTHOR]