The invention discloses a diluent for a hematology analyzer. The diluent for the hematology analyzer comprises sodium chloride, sodium sulfate, a phosphate buffer agent, ethylene diamine tetraacetic acid, 1-pyridone-2-sulphur and formaldehyde, and the pH value of the solution is 6.5-7.4, and preferably is 7.2; the content of each component is preferably as follows: 5g / L of sodium chloride, 10g / L of sodium sulfate, 0.3g / L of ethylene diamine tetraacetic acid, and 0.2ml / L of 1-pyridone-2-sulphur. The diluent for the hematology analyzer provided by the invention has the beneficial effects that general physical mixing can be adopted, and the preparation is extremely convenient; 1-pyridone-2-sulphur replaces the commonly used antimicrobial preservative sodium azide, is non-toxic, is safe to use, and can not cause harm or damage to reagent producers and environments; formaldehyde not only has a preservation effect, but also can keep the completeness of forms and structures of blood cells, and can increase the mechanical injury performance of the blood cells; and the diluent provided by the invention can achieve the testing effect equivalent to that of the original sheath fluid, and the cost is controlled well.