The invention relates to a lithium ion battery positive electrode material, in particular to a lithium ion battery positive electrode material and a preparation method thereof. The preparation methodcomprises the steps of firstly, weighing a lithium salt, a nickel salt and a chromium salt according to stoichiometry, and dissolving the lithium salt, the nickel salt and the chromium salt in absolute ethyl alcohol to prepare a metal salt solution; secondly, stirring a complexing agent solution under an effect of an ultrasonic external field and adding the metal salt solution for reaction, controlling a temperature to 40-60 DEG C, controlling an addition speed of the complexing agent solution so that ions of a reaction system is uniformly dispersed, placing the reacted solution in the ultrasonic external field, adding an acetic acid solution after uniform stirring, adding a titanium salt solution, adding ZrO(C3H7)4 and MgF2, continuing to stir until gel is formed, and obtaining dried gelafter drying and cooling; thirdly, placing the dried gel in a ball-milling tank for ball-milling; and finally, placing the dried gel which is ball-milled in a furnace for calcination to obtain a sample.