Negative-pressure liquid sampler

The utility model discloses a negative-pressure liquid sampler. Sampling bottle, a sealing plug is arranged on a bottle opening of the sampling bottle; an air suction hole and a sample injection holeare longitudinally formed in the sealing plug; an exhaust pipe is inserted into the exhaust hole; a sample injection pipe is inserted into the sample injection hole; the lower ends of the sample injection pipe and the exhaust pipe are spaced from the bottom of the sampling bottle; the exhaust pipe is hermetically connected with the exhaust hole; the sample injection pipe is hermetically connectedwith the sample injection hole, one end of the exhaust pipe, which is positioned outside the sampling bottle, is connected with an exhaust one-way valve and an exhaust device, the air inlet end of theexhaust one-way valve is connected with the exhaust pipe, and the air outlet end of the exhaust one-way valve is connected with the exhaust device; and the open end, positioned outside the sampling bottle, of the sample inject