At present, there are few clinical studies on the application of high-concentration sodium chloride solutions in intracavitary ECG-guided catheter tip localization during the arm infusion port implantation. This study observed the effects of sodium chloride solutions with different concentrations on intracavitary ECG-guided arm infusion port implantation in the patients with cancer. The 657 patients receiving arm infusion port implantation in our hospital between January 2020 and August 2021 were randomly divided into 0.9% sodium chloride solution conduction group (group A), 5.45% sodium chloride solution conduction group (group B) and 10% sodium chloride solution conduction group (group C). The derived rate of stable intracavitary ECG, the occurrence rate of characteristic P wave, the time used for catheter tip localization and the optimal position rate of catheter tip were compared between the three groups. The derived rate of stable intracavitary ECG was significantly higher in the group B (97.78%) and group C (98.63%) than in the group A (93.90%) (all P < 0.05). The occurrence rate of characteristic P wave was also significantly higher in the group B (96.89%) and group C (97.72%) than in the group A (88.73%) (all P < 0.001). The time used for catheter tip localization was significantly shorter in the group B [(49.73 ± 8.15) s] and group C [(48.27 ± 8.61) s] than in the group A [(69.37 ± 19.99) s] (all P < 0.001). There was no significant difference in the optimal position rate of catheter tip among the three groups (P > 0.05). The 5.45% and 10% sodium chloride solutions are significantly superior comparing with 0.9% sodium chloride solution in the derived rate of stable intracavitary ECG, occurrence rate of characteristic P wave and time used for catheter tip localization, but there were no significant differences between 5.45 and 10% sodium chloride solutions. Moreover, the 5.45% sodium chloride solution is closer to physiological state comparing with 10% sodium chloride solution, so the 5.45% sodium chloride solution may be recommended for the intracavitary ECG-guided arm infusion port implantation.