The invention discloses a Turbo decoding device and a Turbo decoding method compatible with two generations of DVB-RCS. The device comprises 16 modules, namely, a rate matching module, two interleaving modules, a de-interleaving module, eight storage modules, a data selection module, a backward measure calculation module, an external information calculation module, and a hard decision module. The method comprises the steps of receiving a data flow, storing an information flow, setting the maximum number of iterations, calculating the backward measure value of a front half wheel, calculating the logarithmic likelihood ratio information and external information of the front half wheel, storing the external information of the front half wheel, calculating the backward measure value of a back half wheel, calculating the logarithmic likelihood ratio information and external information of the back half wheel, storing the external information of the back half wheel, making a decoding termination decision, and making a hard decision. Turbo decoding compatible with two generations of standards is completed in one decoding device, and the consumption of hardware resources is reduced.