The invention relates to an environment-friendly cation emulsified water-based
cutting fluid and a preparation method thereof. The preparation method is characterized by comprising the following steps: preparation of a component A: respectively adding 3-8% of
quaternary ammonium salt, 5-8% of Tween -40, 0.05-0.2% of
calcium chloride, 0.01-0.08% of
magnesium sulfate, 16-30% of
gear oil 200# and 54-76% of deionized water into a reaction kettle for uniformly stirring, heating the mixture until the temperature is within 45-65 DEG C, and keeping the temperature for 20-30 minutes to obtain the component A; preparation of a component B: respectively adding 20-40% of extreme pressure
antiwear additive, 2-10% of
preservative, 5-20% of antirust, 0.04-0.3% of
calcium chloride, 0.01-0.06% of
magnesium sulfate and 30-72% of the deionized water into the reaction kettle for uniformly stirring, heating the mixture until the temperature is within 55-75 DEG C, and keeping the temperature for 25-35 minutes to obtain the component B; and after the component A and the component B are prepared, mixing and stirring the component A and the component B according to the
mass ratio of 2:1-1:2 to be invalid, heating the mixture until the temperature is within 65-80 DEG C, keeping the temperature for 35-45 minutes, and then cooling to normal temperature to obtain the product of the invention. The product of the invention has the advantages of
high wear resistance, water
solubility and lubricating property, good anti-
rust property, no
corrosion, good cooling property, convenient cleaning, cheap price and the like.