This paper briefly introduces the current state in computer modelling of geothermal reservoir system and then focuses on our research efforts in high performance simulation of enhanced geothermal reservoir system. A novel supercomputer simulation tool has been developing towards simulating the highly non-linear coupled geomechanical-fluid flow-thermal systems involving heterogeneously fractured geomaterials at different spatial and temporal scales. It is applied here to simulate and visualise the enhanced geothermal system(EGS),such as(1) visualisation of the microseismic events to monitor and determine where/how the underground rupture proceeds during a hydraulic stimulation,to generate the mesh using the recorded data for determining the domain of the ruptured zone and to evaluate the material parameters(i.e.,the permeability) for the further numerical analysis and evaluation of the enhanced geothermal reservoir;(2) converting the available fractured rock image/fracture data as well as the reservoir geological geometry to suitable meshes/grids and further simulating the fluid flow in the complicated fractures involving the detailed description of fracture dimension and geometry by the lattice Boltzmann method and/or finite element method;(3) interacting fault system simulation to determine the relevant complicated rupture process for evaluating the geological setting and the in-situ reservoir properties;(4) coupled thermo-fluid flow analysis of a geothermal reservoir system for an optimised geothermal reservoir design and management. A few of application examples are presented to show its usefulness in simulating the enhanced geothermal reservoir system. This paper briefly introduces the current state in computer modeling of geothermal reservoir system and then focus on our research efforts in high performance simulation of enhanced geothermal reservoir system. A novel supercomputer simulation tool has been developed towards simulating the highly non-linear coupled geomechanical-fluid flow-thermal systems involving heterogeneously fractured geomaterials at different spatial and temporal scales. It is applied here to simulate and visualise the enhanced geothermal system (EGS), such as (1) visualization of the microseismic events to monitor and determine where / how the underground rupturepting during a hydraulic stimulation, to generate the mesh using the recorded data for determining the domain of the ruptured zone and to evaluate the material parameters (ie, the permeability) for the further numerical analysis and evaluation of the enhanced geothermal reservoir; (2 ) converting the available fractured rock image / fracture data as well as the reservoir geological geometry to suitable meshes / grids and further simulating the fluid flow in the complicated fractures involving detailed lattice of fractures and geometry by the lattice Boltzmann method and / or finite element method; (3) interacting fault system simulation to determine the relevant complicated rupture process for evaluating the geological setting and the in-situ reservoir properties; (4) coupled thermo-fluid flow analysis of a geothermal reservoir system for an optimized geothermal reservoir design and management. A few of the application examples presented to show its usefulness in simulating the enhanced geothermal reservoir system.