The invention provides a special reinforcing agent for ready-mixed pervious concrete and a preparation method thereof. The special reinforcing agent for the ready-mixed pervious concrete includes thefollowing raw materials by mass: 40-45% of anti-cracking component, 20-25% of flexural component, 2%-4% of thickening component, 19-24% of adhesive component and 10-15% of water reduction component. The dosage of the special reinforcing agent in the pervious concrete is 2-3% of the mass of a cementing material. The reinforcing agent can not only effectively prevent the late shrinkage of the pervious concrete and reduce the stress cracking, but also significantly improve the flexural resistance and the frost resistance of the pervious concrete, ensures the mechanical property and the durabilityof pervious concrete pavements, and enhances the water retention and the slump retention of the previous concrete to meet the construction requirements of the ready-mixed concrete. The reinforcing agent is beneficial to prepare the premixed medium and high strength pervious concrete.