The invention relates to a nickel-doped and carbon / silica-coated synergistically modified cobalt lithium fluorophosphates cathode material and a preparation method thereof. The preparation method comprises the following steps: (1) respectively adding a lithium source, a cobalt source, a fluorine source and a nickel source compound into deionized water in a certain stoichiometric ratio, stirring, adding a certain amount of a phosphate source compound into the solution, further stirring, transferring into a high pressure reaction kettle, airtightly heating, reacting, then naturally cooling, taking out, and drying, so that a precursor is obtained; (2) mixing the obtained precursor and a carbon source compound, grinding, and calcining for two stages in inert atmosphere, so that a carbon-coatednickel-doped Li2Co1-xNixPO4F / C material is obtained; and (3) weighing a certain amount of silica, putting into a breaker, adding deionized water, carrying out ultrasonic treatment, then adding the Li2Co1-xNixPO4F / C material, stirring, drying, and grinding, so that the Li2Co1-xNixPO4F / C+SiO2 target material is obtained. The prepared material is uniform in particles and good in crystallinity and has relatively high specific capacity and good cycle performance; and meanwhile, the synthetic process is simple and easy, and the production cost is low.