High price and poor stability of both crocin-1 and crocin-2 reference substance have become obstacles to HPLC assay of Croci Stigma. A new method based on reference extract was proposed. In this study, the reference extract was prepared from gardenia yellow which is cheap and easy to get The content of crocin-1 and crocin-2 in reference extract was determined and factors affecting stability of reference extract were investigated. Twelve batches of Croci Stigma were analyzed with reference extract and reference substance respectively. The results showed no difference. The presented method is feasible for quality control of Croci Stigma and reference extract is suitable to replace reference substances in assay.