The effects of different fineness and dosage of zeolite on flexural strength, compressive strength and fluidity are investigated, and the influence mechanism of zeolite as a mixture on cement hydration is explained. The results show that the fineness of zeolite has a significant influence on the hardened cement. The smaller the fineness of the zeolite, the higher the activity of zeolite, and the higher the strength of the hardened cement at the same age. When the fineness D50 of zeolite is 2.62μm and D90 is 13.35μm, the maximum compressive strength of 28-day is 59.5MPa with 20% content of zeolite, which is 6.1% higher than that of blank sample. When the zeolite content is 40%, the 28-day compressive strength can still reach 46.1MPa. The fluidity has a linear relationship with the zeolite content, but has little correlation with the its fineness. The fineness of zeolite does not affect the type of hydration products, but it affects the quantity of hydration products. The finer the zeolite, the higher the reaction activity, and the more hydration products at the same age, the faster the reaction.