Data allocation is a key problem in layered peer-to-peer streaming with the pattern of multiple senders and single receiver. To improve the requesting nodes’ streaming qualities and to reduce the bandwidth consumption of the root node, the above problem is discussed in two scenarios. The first scenario is that the root node doesn’t participate in the allocation session, and the allocation goal is to maximize the requesting nodes’ streaming qualities. A search and cut accurate algorithm and a heuristic approximation algorithm are presented. The second scenario is with the root node’s participation, and the goal is to satisfy the request nodes’ streaming qualities and to maximally save the bandwidth consumption of the root node. The problem’s computing complexity in the latter scenario is analyzed and a heuristic approximation algorithm is also presented. Simulation studies show that the proposed algorithms have improved performances than the related proposed algorithms with different parameters.