Aircraft Flight Operation Regulations Article 285-31

During taxi, cabin crew members required must remain at their duty stations with safety belts and shoulder harnesses fastened except to perform duties related to the safety of the aircraft and its occupants.
中文原文 航空器飛航作業管理規則第285-31條
當飛機於地面滑行時,派遣之客艙組員應就座於指定座椅並繫妥安全帶,如有裝置肩帶者,並應繫妥肩帶。

English translation for reference only; the Chinese text prevails. Not legal advice.