The invention provides an LIBS (Laser-induced Breakdown Spectroscopy) belt type powdery material detector, comprising a laser source, a focusing lens and an optical detector for receiving a spectral signal, as well as a belt type transmission for conveying powdery materials and a baffle plate, wherein the belt type transmission comprises a conveying belt and a motor for driving the conveying belt to move; the baffle plate is located above the conveying belt; and the optical detection device, the laser source and the focusing lens are arranged on one side of the baffle plate and above the conveying belt. The LIBS belt type powdery material detector employs belt type conveying and obtains a powdery material layer even in thickness by means of the baffle plate; therefore, the technical problem that the distance between the focusing lens and the surface of a sample is difficult to be controlled due to uneven surface distribution of the powdery materials, and the technical effects of continuous sample preparation of the powdery materials, stable LIBS spectral measurement and online powdery material component obtaining are achieved.