The invention relates to a tigecycline freeze-dried powder injection, which consists of tigecycline, dextran, sodium sulfite and sodium citrate according to the following weight proportion: 10 portions of the tigecycline, 10 to 90 portions of the dextran, 0.1 to 3 portions of anhydrous sodium sulfite, and 0.1 to 3 portions of the sodium citrate. The pH value of the tigecycline freeze-dried powderinjection is between 7.0 and 9.0. The preparing process comprises the following steps: firstly, dissolving the dextran by 80 percent of water for injection; secondly, adding the sodium citrate and the anhydrous sodium sulfate into the mixture after cooling; thirdly, adding the tigecycline into the mixture after dissolving and evenly stirring the sodium citrate and the anhydrous sodium sulfate, and mixing the mixture evenly; and fourthly, regulating the pH to between 7.0 and 9.0, adding a needle activated carbon into the mixture, stirring and adsorbing the mixture, removing the activated carbon from the mixture, and fixing the capacity. The solution is filtered through two microporous membranes and then are filled in a cillin bottle, and the tigecycline freeze-dried powder injection is obtained through semi-stoppering, spanning, freeze-drying, introducing nitrogen, performing tamponade, taking out the injection from a box, rolling a mouth, passing the quality inspection, and packaging.