In present work, Sr, Ca and Si elements were added into AZ91D and cast into a metallic mold. The influence of these elements on AZ91D magnesiurn alloy were studied systematically with the purpose of developing a new magnesium alloy with good mechanical properties at both room and high (150 degrees C similar to 200 degrees C) temperature. Additionally, a simple method to qualitatively analyze the high-temperature creep performances of magnesium alloys was designed and implemented.