This study presents a simple and effective tasseled cap transformation based green tide index (TCT-GTI) algorithm by combining the band characteristics of the geostationary ocean color imager (GOCI). By analyzing the identification results of green tide from visual judgement, and comparing them with the monitoring results of two existing remote-sensing algorithms (AFAI and IGAG algorithms), we find that the TCT-GTI algorithm shows relatively high accuracy and reliability. In 2017, the TCT-GTI algorithm is applied to the extraction of green tide information in the Yellow Sea of China using the multi-view GOCI images. We analyze the daily variation characteristics of the green-tide coverage area and study the drift trajectory of the green tide event in 2017. The obtained results show that the green-tide coverage area reaches the maximum at 12:00, which may be influenced by factors such as photosynthesis. This bloom event of green tide in 2017 experiences a drifting trajectory from northwest to the northeast; i.e., it drifts from the offshore waters along Yancheng City in Jiangsu Province, to the east of the South Yellow Sea, then continues to move northeastward, reaches the south bank of the Shandong Peninsula, and gradually disappears.