Magnesium carbonate belonged to high energy consumption products, the energy consumption part of pyrolysis was about 50% of the whole production process. How to reduce the energy consumption of the pyrolysis process had very important significance for magnesium carbonate production. Pyrolysis process to produce magnesium carbonate was improved by the method of carbide in dolomite technology. The heat energy of pyrolysis liquid after recovery was reused for pyrolysis process by this method, the energy consumption of pyrolysis process was reduced by 15%. Using this improved pyrolysis process, not only the heat energy was recovered, and the energy consumption was reduced, but also the temperature of liquid export and the requirements were all reduced , the filter equipment and the equipment investment were also reduced.