Magnesium is one of the essential elements to crop growth and also the core element for chlorophyll. It can accelerate synthesis of various substances, improve crop resistance to disease, promote enzymatic activation, and prevent soil hardening. It can also make root system vigorous for fully absorption of water and nutrients, promote the synthesis of chlorophyll, accelerate the growth of plants, and shorten crops’ growth period. Fruits’ brightness, color and flavour are improved noticeably. Researches have proven that using magnesium fertilizer can increase crop’s yield by 10%-30%.It can also be used as soil amendment which can make neutralization. Magnesium fertilizer not only can be used directly, but also can be used as composition of compound fertilizer.