The invention relates to a building material as well as the manufacturing method thereof, in particular to a glass fiber reinforced gypsum board as well as the manufacturing method thereof. The glass fiber reinforced gypsum board comprises the components by weight parts as follows: 100 parts of high strength gypsum powder, 5 or more than 5 parts of glass fiber choppedstrand mat and glass fiber lattice cloth, (0.2 to 0.5) percent of water reducing agent, (0.1 to 0.5) percent of retarder and 30 to 33 parts of water. The manufacturing method comprises the following steps in sequence: batching, slurry-mixing, mould-entering and casting, finished-product knockout, dehydration and drying as well as shaping and cleaning. The glass fiber reinforced gypsum board has the advantages that the distortion is small, the dry/wet shrinkage rate is low, the strength is high, the weight is light, no odor exists, the board can be degraded for regeneration and utilization, the acoustic effect is good, the material surface is fine and clean, the reinforced gypsum board also has fireproof performance, and meanwhile, the manufacturing process is simple, the construction period is short, and the manufacturing cost is low.