The invention provides a coral reef area spinous-crown starfish collecting device, belongs to the technical field of marine ecological environment treatment, and solves the problems that spinous-crown starfishes are difficult to effectively and quickly collect, capture and convey and the like. Comprising a collecting ship, the upper end of the collecting ship is provided with a placing bin, a lifting hydraulic column and an angle adjusting conveying mechanism, the upper end of the lifting hydraulic column is provided with a main supporting frame, the lower end of the main supporting frame is provided with a rotating mechanism, the lower end of the rotating mechanism is provided with a telescopic conveying mechanism, and the front side of the rotating mechanism is fixedly provided with a connecting frame; a medicine injection mechanism and an adjusting mechanical arm are arranged at the lower end of the telescopic arm mechanism, a clamping jaw mechanism is arranged at the end of the adjusting mechanical arm, and a containing cloth bag is arranged on the rear side of the lower end of the rotating mechanism. The device can quickly clamp, collect, capture and convey the spinous crown starfish, quantitatively inject medicine to the spinous crown starfish, quickly kill the spinous crown starfish, and facilitate later collection; and the method also can introduce the lava into the coral area for biological control, and is good in effect and low in cost.