A simple method of preparation of organic magnesium compounds (citrate, acetate and aspartate) from natural dolomite with simple apparatus was worked out. In the first stage dolomite was converted into magnesium sulfate and then into basic magnesium carbonate by combination with citric and acetic acids. However, magnesium aspartate was prepared by converting magnesium sulfate into hydroxide and then combining it with aspartic acid. The contents of trace element were determined in the final preparations with ASA. Thermal decompositions of the obtained compounds was studied by means of the thermal analysis. Results could be useful in elaborating method of production of these magnesium compounds from domestic dolomite.