A throwing-into type 
ultraviolet absorption on-line analyzer belongs to the technical field of 
water quality detection apparatus equipment, is used for in-situ detection of 
water quality in water; the technical scheme comprises: the analyzer comprises an housing body, a measuring 
pool, a power supply, a measuring unit, a reference unit, a 
control unit; the measuring 
pool is mounted inside the housing body; the power supply is mounted at one side of the measuring 
pool in the housing body; the measuring unit, the reference unit, the 
control unit are mounted at the other side of the measuring pool in the housing body; light through holes passing through the measuring pool are disposed along an axial direction of the measuring pool; a water inlet is disposed at the central part of the measuring pool; lenses are respectively mounted in light through hole cavities which are located at two sides of the water inlet of the measuring pool and face each other; the axis of the lenses, the 
optical axis of the power supply, and the 
optical axis of the measuring unit are on the same straight line; the measuring unit is arranged to have a 10 DEG-30 DEG angle with the reference unit; 
signal output ends of the measuring unit and the reference unit are connected to the 
control unit. According to the invention, the analyzer can be directly thrown into the water to be detected for monitoring, and the measurement is convenient and rapid, does not require sampling, and saves cost.