The present invention relates to aqueous binder composition capable of recycling process water and method for binding fibrous materials by using the same, and relates to an aqueous binder composition comprising one or more reducing sugars, one or more amino acids and aldehyde compounds with minimum inhibitory concentration (MIC) 1% or less and a method for binding fibrous materials by using the same. The binder composition of the present invention provides equal or better physical properties with lower price compared to traditional phenol formaldehyde resin (PFR), does not include or release toxic materials such as formaldehyde or phenol, may decrease bad odor which is a vulnerable point of traditional PFR during manufacturing and remarkably enhances the mechanical properties such as water resistance, tensile strength and hardness of the manufactured product, and is economical since process water can be recycled without putrefaction which occurs during the manufacturing process of binding of fibrous materials using the binder component since the binder solution has preservative ability.