Abstract: FlexE technology, as an effective solution for building a new power information communication network, can realize multi-service slicing and co-bearing at the same time, but the introduction of FGU brings corresponding problems. This paper firstly clarifies some problems and technical challenges faced by the introduction of FlexE technology in multi-granular slices, and then analyzes the impact on the performance of the system from the node and end-to-end delay, two-way delay problem and multi-frame phase change brought by FGU. Finally, the optimization measures with the combination of the time slot scheduling algorithm and the multi-frame phase alignment of the forwarding plane have carried out the design of FGU time slot scheduling algorithm of the FlexE network, which improves the system performance.