Objective To develop an accurate, rapid and simple colloidal gold immunochromatographic test (ICT) for detection of THC in urine. Methods Colloidal gold was prepared by reduction of HAuCl4 with trisodium citrate. Anti-THC monoclonal antibody was then labelled with the colloidal gold. THC-BTG conjugate was coated on nitrocellulose membrane to prepare test strip. Result could be detected by naked eyes because the competition for limited antibody binding sites on either THC-BTG conjugate or free THC which may be present in urine samples. Results A total of 216 urine samples were detected for THC by ICT and GC/MS. The detecting limit of the ICT was 50ng/ml, the sensitivity waw 96.67% and the accuracy was 98.61%. Conclusion ICT is a specific assay for detection of THC in urine.