An ion implantation system including an ion implanter, a dopant source gas supply system and a monitoring system is provided. The ion implanter is inside a housing and includes an ion source unit. The dopant source gas supply system includes a first and a second dopant source gas storage cylinder in a gas cabinet outside of the housing and configured to supply a dopant source gas to the ion source unit, and a first and a second dopant source gas supply pipe coupled to respective first and second dopant source gas storage cylinders. Each of the first and second dopant source gas supply pipes includes an inner pipe and an outer pipe enclosing the inner pipe. The monitoring system is coupled to the outer pipe of each of the first and the second dopant source gas supply pipes.