Transferring DNA into cells to regulate cell function is a novel research field in recent decades.Chitosan is a gene vector with the properties of low-cost and safe，but high efficient delivery has remained challenging. We developed a strategy termed EEIH，for endosomal explosion induced by hypertonicity, in which short-time exposure to hypertonic solutions triggers endosomes destabilization like explosions. EEIH can force chitosan/DNA polyplexes to break through the endosomal barriers to approach the nucleus, which results in boosting the transfection efficiency of chitosan in several cell lines. We demonstrate that EEIH is a significant and practical strategy in chitosan transfection system without sophisticated modification of chitosan.