The invention relates to a method for quickly detecting size distribution of calcium carbonate by utilizing near infrared spectroscopy. The invention discloses a near infrared detection method for the size distribution of calcium carbonate. The method comprises the following steps: (1) collecting and preparing a representative calcium carbonate sample; (2) collecting an original spectrum; (3) determining a sample reference value; (4) carrying out spectral pretreatment; (5) establishing a PLS (Partial Least Squares) model; (6) optimizing and evaluating the model; and (7) determining the size distribution of calcium carbonate. In the detection method provided by the invention, the original spectrum of the calcium carbonate sample is acquired, the partial least squares is used for establishing the model, the median particle diameter of calcium carbonate and the proportion of the grain size less than 2um are detected. The method is characterized by high detection speed, accurate result, suitability for analysis test of mass samples, simple test process, no damage to the sample, no chemical reagent, and benefit to environment and occupational health.