The invention relates to a magnesium-aluminum-titanium-carbon intermediate alloy which comprises the following chemical components in percentage by weight: 65.00-98.00% of Mg, 1.00-13.00% of Al, 0.40-12.00% of Ti and 0.60-10.00% of C. The preparation course provided by the invention can be finished at quite low temperature, the absorption rate of the carbon is high, and the reaction is complete. Meanwhile, the presence of the titanium carbide can ensure that the main nucleation phase aluminum carbide is formed by being attached on the surface of the titanium carbide, and thus, the intermediate alloy is finer and the distribution is more uniform. The method provided by the invention has the characteristics of high production efficiency, low cost, good refinement effect of the prepared magnesium-aluminum-titanium-carbon intermediate alloy and the like, and is suitable for mass production and application.