Backend system, as a part of the radio telescope, receives the radio signal which is amplified by the receiver, lays its emphasis on signal digitization and processing, and sends the processed data into storage system. Digital backend as a standard facility of radio telescope takes the place of analog backend, and multi-functional backend system is on its way to perfection. The backend hardware platforms, such as FPGA, GPU, CPU, and MIC, and they can be chosen when designing radio telescope backend system. The 110 m radio telescope (QTT), which is proposed to be built in Xinjiang Qitai, is planned with L, S, C, K wide/ultrawide band single pixel receivers, L band PAF and Q, W band conventional multibeam receivers, and the adaptive ultrawide band digital backend system will also be designed. Based on development of radio telescope backend system and introduction of worldwide research frontiers, we discussed and designed the digital backend plan and roadmap for QTT.