The invention discloses a full-automatic analyzer of a water soluble sulfide compound and an analysis method. The full-automatic analyzer comprises a sample pretreatment device and a chromogenic detection device, wherein the sample pretreatment device comprises an autoinjection device, a first peristaltic pump, a distillation reagent container, a first triple valve, a first line heat module, an on-line distillation module and an on-line degasser; and the chromogenic detection device comprises a second peristaltic pump, a current carrying bottle, a developer bottle, a ferric chloride solution bottle, a sampling ring, a six-way valve, a second backpressure regulator, a second triple valve, a first knotted reactor, a third triple valve, a second line heat module, a flow-through cell, a detector, a waste liquid bottle, a data connection cable, a computer processing system and a first backpressure regulator. The invention also discloses an analysis method of the water soluble sulfide compound. According to the full-automatic analyzer of the water soluble sulfide and the analysis method, samples can be continuously and automatically tested with the detection limit being 1 microgram/L, and the test is accurate and rapid.