The invention relates to a water-containing high-purity argon monitoring system and method. The water-containing high-purity argon monitoring system comprises a view tank, a ball valve B, a diversion drainer, a dryer, a filter, a sampling pump, a throttling valve, a flowmeter B, a trace oxygen analyzer and a check valve which are mounted between a sampling opening and a gas outlet of an argon-filled container and sequentially connected, wherein a ball valve is mounted on a bypass of the ball valve B and the diversion drainer; a liquid discharge pump is mounted on a first branch pipe connected with the diversion drainer; a liquid discharge opening is formed in the end part of the first branch pipe; a thermometer is mounted on a connecting pipe between the diversion drainer and the dryer; an overload protection loop is arranged on a bypass of the sampling pump; a flowmeter A and a safety valve are mounted on the overload protection loop; a ball valve C is mounted on a second branch pipe connected with the pipeline between the sampling pump and the dryer; a calibration opening is formed in the end part of the second branch pipe. The water-containing high-purity argon monitoring method comprises four stages; a calibration stage, a draining and purging stage, a measurement stage and a computation stage.