【Objective】Magnesium (Mg) is a mineral nutrient essential to plant growth. It is the central atom of chlorophyll, and also an activator of various enzymes, involved in various metabolic reactions in plants. Magnesium deficiency can affect normal growth and yield quality of the crops involved. Nevertheless it has become more and more a common problem in the soil-crop systems in South China, in the last decades, where though large volumes of chemical fertilizers are applied, little magnesium fertilizers are, and the removal of magnesium by crop and soil Mg leaching is high. Mg leaching in the soil is one of the primary factors leading to Mg deficiency in the soil and crops in the tropical and subtropical regions of China with high temperature and plentiful rainfall. To solve the problem, application of magnesium fertilizer has become an important strategy. Therefore, it is of great importance to explore characteristics of Mg movement and leaching in Mg deficient soils as affected by Mg fertilizer application for rationalizing application of Mg fertilizers.【Method】An indoor soil column simulation experiment was conducted to study movement and leaching of Mg in the three types of acid Mg-deficient soils (red soil, yellow soil and purple soil common in South China), applied with magnesium oxide (MgO), improved magnesium sulfate (Improved MgSO₄, pH>8), calcium magnesium phosphate fertilizer (CaMgP) and potassium sulphate magnesium (KMgS), separately, and consequently efficiency of the fertilizers. This study is expected to be able to provide certain technical support for rationalization of the application of Mg fertilizers in the soils typical of South China. 【Result】Results show that soil exchangeable Mg increased by 2~15 folds in all the three types of soils (0~15 cm) after application of the Mg fertilizers at a rate of MgO 100 mg·kg^-1 . Among the four types of Mg fertilizers, Improved MgSO₄ was the highest in the effect and followed by CaMgP, MgO and KMgS, sequently. After 60-days of leaching with simulated rainfall amounting to 1000 mm, strong downwards movements of soil Mg in the soils applied with MgO, improved MgSO₄ or KMgS fertilizer were observed. Compared with the soils with no Mg applied (CKs), the soils applied with Mg fertilizer had soil exchangeable Mg increased in concentration significantly or by a range of 17.9~105.4 mg·kg^-1 in the 15~50 cm soil layer as a result of leaching of Mg from the top layer (0~15 cm). The effect was significant in the yellow soil and red soil applied with CaMgP, but not in the purple soil. In general, Mg concentration in leachate displayed a trend, increasing first and then decreasing, which could be well described with a quadratic equation. Accordingly, the amount of leached Mg from the soils under different Mg treatments could be well matched by exponential equations. The accumulated Mg leaching from the yellow soil varied in the range of 104.9~243.8 kg·hm^-2 , which was close to that from the purple soil, and 2~3 times higher than that from the red soil. Compared with CKs, application of MgO, improved MgSO₄ or KMgS fertilizer significantly increased the amount of Mg leaching in the yellow soil and purple soil, while application of CaMgP fertilizer did reversely. After the leaching experiment, the leaching rates of the MgO, improved MgSO₄ and KMgS fertilizers applied in the yellow soil and purple soil were all higher than one-third, whereas lower than 7% in the red soil. On the other side, application of CaMgP enhanced retention of Mg in the soils, and slowed down the downwards movement of Mg, thus reducing Mg leaching during the leaching experiment period as compared with CK. 【Conclusion】By considering integratedly the effects of the four types of magnesium fertilizers on availability, retention and leaching of Mg in the soil and retardation of soil acidification, CaMgP fertilizer is preferred for all the three types of acid soils typical of South China, although its biological availability needs to be studied further.