Objective To explore the influence of improved flushing method on the maintenance of venous indwelling needle. Methods 339 patients using venous indwelling needle from April 1 to June 30, 2021 were selected as the control group, and 352 patients from July 1 to September 30, 2021 were selected as the observation group. The control group used the traditional A-C-L flushing method (Evaluation-flushing-sealing method) for catheter maintenance in the process of using indwelling needle, while the observation group used the improved flushing method for catheter maintenance. Results The blood return rate of indwelling needle and the incidence of catheter blockage in the observation group were significantly lower than those in the control group, and the indwelling time was significantly longer than that in the control group (all P<0.05). Conclusion In the process of using venous indwelling needle, the improved "A-C-L" catheter maintenance technique can reduce the incidence of complications and prolong the time of indwelling needle.