A transmission control method during regenerative braking of a hybrid vehicle is directed to providing a transmission control method during regenerative braking of a hybrid vehicle that is capable of accurately estimating the regenerative braking execution amount, by constantly controlling the transmission output torque, that is, the regenerative braking execution amount, until the transmission input speed reaches the speed corresponding to the target transmission stage, through the operating element torque and motor torque intervention control for transmission, when transitioning to the target transmission stage from the current transmission stage of the multistage automatic transmission of the hybrid vehicle, and is capable of accurately estimating the regenerative braking execution amount and simultaneously securing the braking linearity during transmission.