The invention relates to a sampling method and a device, and especially relates to an intelligent sampling weighing method and a device. The placement range of a to-be-detected piece is identified through an image recognition technology. An infrared generator randomly generates a beam of red light in the range according to the placement range. A piece specified by the irradiation point of the beam of red light is a sample, and the sample is detected. The red light generation process and the detection process are recorded in the form of video. The beneficial effects are as follows: the sample collection link is guided and standardized using the image recognition technology and a random cursor generation device, the whole process is recorded in the forms of image and video, non-artificial and intelligent sample detection is realized, and dirty trick in sampling and detection is eliminated; and an objective and fair detection process is ensured.