The invention relates to the field of biochemistry, in particular to recombinant human growth hormone sterile powder for injection and a preparation method thereof. The recombinant human growth hormone sterile powder for injection is prepared from, by weight, 1.5-2 parts of recombinant human growth hormones, 35-75 parts of excipient, 0.5-5 parts of antioxidant, 0.05-0.5 part of surface active agent, 0.4-0.6 part of disodium hydrogen phosphate and 0.1-0.3 part of sodium dihydrogen phosphate. The preparation method of the recombinant human growth hormone sterile powder for injection comprises the steps of A, weighing, wherein the accessories with the weight parts are weighed; B, dissolving, wherein all the accessories are individually dissolved and then mixed, the recombinant human growth hormones with the weight parts are added, and the volume is fixed; C, filtering; D, filling, wherein a bottle is filled with the filtered solution; E, freeze-drying, wherein the filled bottle in step Dis subjected to pre-freezing, vacuumizing, lyophilizing and desorption drying, and freeze-drying is carried out; F, capping. The recombinant human growth hormone sterile powder for injection is good in appearance, dense and uniform in structure and good in stability and activity, the product quality is not influenced in the transportation and use process, and useful life of the product is long.