Atmospheric pressure solids analysis probes (ASAP) ion source is a relatively new type of ion source technology. The technique has broad prospect in the applications of detection of chemical contaminants. As one of the rapid screening method, ASAP is receiving more attentions. The principle, structure and characteristic of ASAP were introduced. The practical examples about quantitative and quantitative analysis of chemical contaminants in grain and oil food were introduced. The application of ASAP ion source was analyzed from hardware and methodology point of view. The ASAP ion source technology used as rapid detection of contaminants in grain and oil products have great value in practice.