The invention provides an epitaxial structure for a high-performance DFB laser. The epitaxial structure comprises an InP substrate; an N-InP buffer layer, N-AlInAs limiting layer, a non-doped AlGaInAslower waveguide layer, a non-doped AlGaInAs quantum well, a non-doped AlGaInAs upper waveguide layer, a non-doped P-type doped AlInAs limiting layer, a non-doped P-InP transition layer, a non-doped InGaAsP grating layer, a non-doped InP connecting layer, a first non-doped InGaAsP barrier gradient layer, a second non-doped InGaAsP barrier transition layer and a non-doped InGaAs ohmic contact layerare sequentially deposited on the InP substrate from bottom to top; and a first tensile strain non-doped InGaAsP heterojunction superlattice layer and a second compressive strain non-doped InGaAsP heterojunction superlattice layer are inserted into the non-doped P-InP transition layer. The epitaxial structure for the high-performance DFB laser of the invention is formed through a rear diffusion process; a carrier injection region is strictly defined; and an obtained DFB laser has the advantages of low threshold value, low series resistance, high modulation rate, great temperature characteristic and high reliability.