The invention discloses a device for measuring zinc in water by virtue of flow injection spectrophotometry and a method for measuring zinc in water, wherein the device has relatively high sensitivity and good selectivity and can be directly applied to determining trace zinc in environmental water. The device is characterized by being composed of a water sample pump (3), a buffer solution pump (5), a chelating agent solution pump (7), a masking column (8), a first complexing agent pump (10), an eluent pump (12), an enrichment-elution column (14), a buffer solution pump (16), a second complexing agent pump (18) and a detection chamber (22), wherein the water sample pump (3), the buffer solution pump (5) and the chelating agent solution pump (7) are connected with the inlet end of the masking column (8) by use of pipelines; the first complexing agent pump (10) and the eluent pump (12) are connected with the outlet end of the masking column (8) by use of pipelines; the eluent pump (12) is connected with the inlet end of the enrichment-elution column (14) by use of a three-way valve; and the buffer solution pump (16), the second complexing agent pump (18) and the detection chamber (22) are connected with the outlet end of the enrichment-elution column (14). The invention also discloses a method for measuring zinc in water.