The invention discloses a preparing technology of a glass fiber composite material. A glass fiber monofilament is soaked in first slurry, then basic glass fiber fabric is obtained through plain weave, and preformed glass fiber fabric is obtained through treatment, finally second slurry is coated at the two sides of preformed glass fiber fabric, and the glass fiber composite material is obtained through ultraviolet solidification. According to the preparing technology of the glass fiber composite material, the first slurry is fully soaked on the surface of the glass fiber monofilament, the mechanical strength of the glass fiber monofilament is improved, and after the glass fiber monofilament is woven into the glass fiber fabric, coating of the second slurry further improves the mechanical strength of the product, and makes the product have good waterproof performance.