The crystallization of salts in three kinds of saline soil was studied,with polarizing microscope and of scanning electron microscope (SEM).It was found that the crystallization order depended on temperature,and under different temperature the main salts in soil solution were determined rapidly.The morphology of several salts in soil were studied by SEM Technique.It was found that halite (NaCl) Pras closely cemented with soil particles,thenardite (Na₂SO₄) was transformed from mirabilite (Na₂SO₄·10H₂O) by dehydration,and the glaubcrite [Na₂Ca(SO₄)₂] was formed by calcium sulfate and sodium sulfate.These salt crystals separated were clear,without any mixture.They would be formed in complex salt under certain conditions.As an example,the condition which affected the transformation of mirabilite-thenardite and its effect on the development of soil structure are discussed.