The present invention relates to a magnesium-based alloy, and to a method for producing same. The method comprises the steps of: melting a magnesium alloy into a liquid state; adding a silicon compound to said molten magnesium alloy; exhausting the silicon compound through a full reaction between said molten magnesium alloy and said added silicon compound such that the silicon compound does not substantially remain in the magnesium alloy; and exhausting the silicon produced as a result of said exhaustion in the precious step such that the silicon may not substantially remain in said magnesium alloy.