A sitting posture sensing chair of a sitting posture assessment system is provided with a plurality of pressure sensors for sensing the pressure while user is sitting thereon. When a mobile electronic device receives the sensing results of the pressure sensors, the sensing results are transmitted to a cloud server which determines whether the sensing results comply with a predetermined condition representing that the user maintains an incorrect sitting posture for a first predetermined time period or a correct sitting posture for a second predetermined time period. When the cloud server determines that the sensing results of the pressure sensors meet the predetermined condition, the sitting posture sensing chair or the mobile electronic device is configured to output an prompt output indicating that the user has maintained the incorrect sitting posture for a first predetermined time period or the correct sitting posture for a second predetermined time period.一種坐姿評估系統的一坐姿感測椅設有多個用於感測該使用者乘坐時之壓力的壓力感測器。當一行動電子裝置接收到該等壓力感測器的感測結果時，將該等感測結果傳送至一雲端伺服器，該雲端伺服器判斷該等感測結果是否符合一代表該使用者坐姿不良維持一第一預定時間或該使用者坐姿正確維持一第二預定時間的預定條件。當該雲端伺服器判斷該等壓力感測器的感測結果符合該預定條件，該坐姿感測椅或該行動電子裝置輸出一指示該使用者坐姿不良維持該第一預定時間或該使用者坐姿正確維持該第二預定時間的提示輸出。
