Dimethyl pentanediamine is mainly used as curing agent for epoxy resin in phenol-acetone plant. It can improve the elasticity of polyurethane hot melt adhesive and prolong its exposure time in the air. Dimethyl pentanediamine has two primary amine functional groups, and the functional groups have different reactivity. The epoxy resin produced with dimethylpentanediamine as curing agent has low addition viscosity, and its elasticity can promote the improvement of resin formula.