The invention discloses anti-adhesion flushing fluid for a gynecological operation and a preparation method thereof and belongs to the technical field of flushing fluid for operation. Every 1L of the flushing fluid disclosed by the invention is prepared from the following raw materials in grams by weight: 30-50g of icodextrin, 4.5-6.5g of sodium chloride, 0.1-0.5g of calcium chloride, 0.01-0.1g of magnesium chloride, 4.0-5.0g of sodium lactate and a proper amount of water for injection. The invention also provides a method for preparing the flushing fluid. According to the invention, an anti-adhesion effect of icodextrin is fully utilized, and the calcium ion, magnesium ion and sodium lactate are added; due to the addition of the calcium ion and magnesium ion, the antibacterial and bacteriostatic abilities are enhanced, and wound healing is promoted; the sodium lactate serves as a pH buffer agent, so that normal osmotic pressure and pH value in the abdominal cavity can be guaranteed, and side reactions are reduced; and moreover, the flushing fluid disclosed by the invention is high in stability, difficult to degrade and denature, good in flushing effect and anti-adhesion effect, non-irritating to skin and convenient to use.