The invention discloses a
seawater quality on-line monitoring device and a monitoring method, and relates to the technical field of
water quality monitoring. Comprising a detection cabin, the top of the detection cabin is fixedly connected with a fixed seat in a penetrating mode, a
water quality monitor is installed in a blocking cover at the bottom of the fixed seat, a first elastic telescopic rod is fixedly installed at the center of the fixed seat, and a partition plate is fixed to the movable end of the first elastic telescopic rod; a triggering
assembly is arranged between the sliding rod and the inner bottom wall of the detection cabin, and a sealing plate is fixed to the right end of the sliding rod. By arranging the adjusting
assembly, the detection depth can be automatically adjusted according to the flow velocity of
seawater, it is ensured that obtained data can represent the real characteristics of disturbed water masses, by arranging the detection cabin, the water inlet, the sealing plate and the triggering
assembly, sampling and isolation detection are conducted on a
water body at the specific depth, and reading is stable; and the
water quality detection sensor is in a closed dry environment in a non-detection period.