The invention belongs to a composition of four-component lithium complex grease and a preparation method thereof. 12-lithium hydroxyl stearate, lithium azelaic acid or lithium sebacic acid, lithium boric acid and lithium salicylate are added into base oil. Four-component complex lithium prepared by controlling complex saponification temperature and time in a first step, alkali adding temperature in a second step, complex co-crystallization temperature and time and the highest temperature by a two-step saponification process has the advantages of high adhesion property, excellent high temperature leakage resistance, long high-temperature bearing service life, high comprehensive performance and capability of meeting the requirement of the lubricating of high-temperature environment equipment and high-temperature centralized pumping and lubricating. The lithium complex grease of the invention belongs to high-temperature grease of which the dropping point is not less than 260 DEG C and which has the prominent advantages of high adhesion property, excellent high temperature leakage resistance and long high-temperature bearing service life at the temperature of 160 DEG C. Compared with polyurea grease, the lithium complex grease cannot be hardened at a high temperature; and compared with the ordinary two-component or three-component complex lithium, the lithium complex grease has the advantages of high adhesion property, excellent high temperature leakage resistance and long high-temperature bearing service life.