The present invention relates to a method of economical extraction of magnesium, boron and calcium, while minimizing the loss of lithium, from a lithium bearing solution. More specifically, the present invention provides a method for economical extraction of magnesium, boron, and calcium, while minimizing the loss of lithium, from a lithium bearing solution comprising the steps of: (a) adding an alkali in the lithium bearing solution to precipitate magnesium hydroxide; (b) absorbing boron ions on the surface of the magnesium hydroxide by adjusting the pH to about 8.5 to about 10.5; and (c) simultaneously extracting magnesium and boron by filtering the magnesium hydroxide absorbed with the boron ions from the lithium bearing solution.