A method using coloric and spectrophotometric detection have been developed for the identification of the tertiary or quaternary alkaloids contained in Corydalis tuber and its preparations. The principle is based on the formation or decomposition of complex compounds. The complex compound of the tertiary and quaternary alkaloids have been formed by adding tetrathiocyanatocobaltate [II] ion to the test soln. Diverse crude drugs were screened using this method and the results indicated that isoquinoline, aconitine-type alkaloids in crude drugs can be readily detected. The method is simple, convenient, reproducible and applicable to the verification of the crude drug Corydalis tuber and its preparations.