The invention provides red up-conversion fluorescent powder and the preparation method thereof, which relates to up-conversion fluorescent powder and the preparation method thereof. The invention solves the problems existing in the prior art that during the production of red up-conversion fluorescent material, the process is complex, the synthesis temperature is high, the cost is high, the dimension of product grains is large, the grain size distribution is non uniformly, and the single-color suppression ratio is small. The system structural formula of the red up-conversion fluorescent powderis NaY1-x-y-z (YbxHoyCez) F4; the method comprises the steps that required raw material is mixed in proportion, reactant is taken out after the stirring, the heat preservation, and the cooling are performed, and the red up-conversion fluorescent powder is obtained after the reactant is centrifuged, cleaned, and dried. The invention adopts a hydrothermal method, the preparation process is simple, the synthesis temperature is only at 180 to 220 DEG C, the cost is low, the obtained product is nano-level, the grain diameter is 70 to 100 nm, the grain size distribution is uniform, and the emissionof the red spectrum peak having larger single color suppression ratio is realized.