Utilization method of middle-low grade phosphate ore containing rare earth

The invention discloses a utilization method of middle-low grade phosphate ore containing rare earth. The method comprises the following steps: carrying out fine grinding on the middle-low grade phosphate ore containing rare earth, adding acid for dissolution, separating slag from a solution, then adding a base in a dissolution liquid to regulate the pH to 1.5-2.5, precipitating rare earth and other metal ions, and separating precipitate enriched with the rare earth from the solution so as to obtain a precipitate A containing above 3% of rare earth; extracting out rare earth from the precipitate A according to a conventional rare earth extraction method; adding a solution B after separation in ammonia water, regulating the pH to 6.5-7.5, and drying the solution so as to prepare a phosphorus-nitrogen-calcium composite fertilizer containing above 8% of phosphorus; or adding ammonia water in the solution B after separation, regulating the pH to 4.5-6, separating the precipitate out and drying so as to obtain dicalcium phosphate, and drying the solution so as to obtain an ammonium nitrate or ammonium chloride product. By using the method, useful resources (such as rare earth, phosphorus, calcium and the like) in the middle-low grade phosphate ore containing rare earth are utilized to the greatest extent.