Plainly weaved fiberglass window screen is made up of fiberglass monofilaments coated with vinyl resins by adopting a special technique. The two substances are thus combined in their good property, and fashioned into grid-like products after appropriate arranging, weaving and heat styling. This product has many favorable properties, such as easy washing, erosion-proof, strong tension, no distortion, no absorption, good light transmittance, and long working life, etc