Abstract: A new type of poly(urea formaldehyde) microcapsules was prepared using urea formaldehyde resin as shell material and modified amine 1618 as core material by interfacial polymerization process. The effects of mass ratio of core and shell(mCore∶mShell), the type of emulsifier, mass fraction of emulsifier and stirring speed on encapsulation rate, the particle size and distribution of microcapsules were investigated by orthogonal experiment. The particle size, distribution and surface topography of microcapsules were characterized using Malvern laser particle size analyzer and scanning electron microscopy. The compositions of microcapsules were characterized using TG DTA and Fourier transform infrared spectroscopy. The mechanical properties were evaluated using tensile testing machine. Results showed that mold curing agent of modified amine was encapsulated in the microcapsule and the decomposition temperature of the microcapsules was about 197 °C. When the mCore∶mShell was 0.7∶1, mass fraction of Arabic gum (used as emulsifier) was 1.5% and stirring speed was 800 r/min, the encapsulation rate was 79.8%, the mean diameter was 207.5 nm and the microcapsules exhibited uniform round and compact surface. The addition of microcapsules in epoxy matrix can improve its mechanical properties. When the mass fraction of microcapsules was 1%, the tensile strength and elasticity modulus of matrix were increased by 64% and 287%, respectively.