The invention relates to a material automatic sampling system and a sampling method. The sampling system includes a conveyor, a hoister, a material guide hose pipe and a controller. A tee joint material guide mechanism communicated with the material guide hose pipe is disposed thereunder. The bottom of the tee joint material guide mechanism is equipped with a sample distribution collection mechanism, and the controller is in electric connection with the tee joint material guide mechanism and the sample distribution collection mechanism respectively. When sampling is needed, the tee joint material guide mechanism is opened, and materials enter the sample distribution collection mechanism through the tee joint material guide mechanism for storage. Compared with the prior art, the system andmethod provided by the invention carry out sampling before materials enter a material bin through a mixer, can avoid the cross mixing phenomenon of different batches of materials during sampling in the material bin, effectively guarantee the accuracy of sampling, can realize accurate sampling of all batches of materials, greatly improve the detection accuracy, are easy to operate, also avoid wasteof materials, and ensure stable production.