The invention discloses a treating fluid for a cultural relic collection packaging material and a treating method thereof. The treating fluid comprises a component A and a component B. The component A consists of the following materials: 10 weight parts of W-18 wax emulsion and 120 to 150 weight parts of water; and the component B consists of the following materials: 10 to 15 weight parts of boric acid, 13 to 15 weight parts of borax, 8 to 12 weight parts of sodium octaborate, 6 to 12 weight parts of sodium fluoride and 1,000 weight parts of water. The treating method comprises the following steps: firstly, placing a material to be treated in the component A, and drying the material in shade after immersing; and secondly, placing the material in the component B and drying the material in the shade after immersing, namely finishing the treatment on the cultural relic collection packaging material. Through detection, the material treated by the treating fluid and the treating method has good fire resistance, has insect expelling and mildew proof effects with non-volatility, odorlessness, high efficiency and low toxicity, has a buffering effect on an acidic gas in air, overcomes influences on cultural relics, a preservation environment and a human body caused by a volatile insect repellant and a mildew preventive, has the characteristics of low cost, convenient purchase, and convenient transport and storage, and has wide market development prospect.