Graphene plasmonic (GP) in terahertz spectral range has been used to enhance the linear and nonlinear optical properties of conic-shaped InAs/GaAs quantum dots (QDs) coupled to wetting layer. Single layer graphene flakes with rectangular geometry in three configurations were located beneath the wetting layer (WL) and by exciting the plasmonic edge modes the transition dipole moments (TDMs) of S-to-P transition were calculated. Optimization on distance and thickness has been done to reach highest TDM. The results showed that the real and imaginary parts of linear susceptibility were enhanced ten and eighteen times, respectively. For third-order susceptibility, seven hundred and twelve thousand times enhancements have been observed for real and imaginary parts, respectively. • Graphene plasmonic has been used in quantum dots. • Plasmonic edge modes of graphene were excited in emission frequency of quantum dot. • Huge enhancements in optical properties were observed in linear and third-order susceptibilities.