Regenerative braking mode is widely used in urban rail transit train, when regenerative braking energy is back to the catenary, it is absorbed by nearby running train, and surplus regenerative braking energy is absorbed by regenerative braking energy absorption system to limit the high catenary voltage. Currently, the regenerative braking energy absorbing device installation location to mainly includes train and substations. At different installation location, impact of DC traction power supply system is different. In this paper, two types of DC traction power supply system flow calculation model were established, parallel operation of multiple trains and multiple substations is simulated and analyzed and get the influence of traction power supply system voltage, current and regenerative braking power allocation under different types of regenerative braking energy absorption system.