The invention discloses an atenolol injection. The atenolol injection is prepared from atenolol and pharmaceutically acceptable auxiliary materials, and the concentration of the atenolol injection is 0.45-0.55mg/mL according to the concentration of atenolol. The auxiliary materials comprise the following components: a composite solvent consisting of 1,2-propylene glycol and water, a buffer system consisting of sodium dihydrogen phosphate and disodium hydrogen phosphate, sodium chloride which is taken as an osmotic pressure regulator, and sodium edetate which is taken as a metal ion complexing agent, wherein in the composite solvent, the volume percentage of 1,2-propylene glycol accounts for 10-35%. The invention also discloses a preparation method of the atenolol injection. By adopting a mode of adding carbon twice, the purpose of adsorbing pyrogen in the injection can be achieved, and a main medicine of a solution cannot be significantly adsorbed. The atenolol injection prepared by adopting the method disclosed by the invention is good in stability and safe and effective in clinical use.