Objective To p repare colloidal gold strip for rap id detection of Sudan Ⅰ. Method Preparing 20 nm colloidal gold particles with trisodium citrate, labeling them with anti2Sudan ⅠMcAb, and installing strip s and testing in lab. Results Under laboratory conditions, SudanⅠin food samp les could be tested by colloidal gold strip s in few minutes. The lowest concentration for detection was 50 ng/L. Conclusion In comparison with other detection methods, the colloidal gold strip method ismore rap id, friendly in use and relatively inexpensive.