The invention discloses selective laser sintered polyimide powder and a preparation method thereof. The preparation method comprises steps as follows: 1) under the protection of nitrogen or argon, diamine is added to an ion solvent, the mixture is heated to 25-60 DEG C and stirred for full dissolution, and the solution is cooled to the normal temperature for use; 2) dianhydride is added to the solution obtained in Step 1) in batches at the time interval of 20-40 min, then the solution is gradually heated to 120-260 DEG C, the continuous reaction is performed for 2-24 h, washing and drying treatment are performed sequentially, and the selective laser sintered polyimide powder is obtained. The diamine is imidized in the ion solvent in one step, the prepared polyimide powder is high in imidization degree and heat-resistant stability, and parameters of particle size distribution, apparent density, morphology and the like of the polyimide powder meet the requirement of the selective laser sintering forming technology.