Multicast at WDM layer by light splitting is considered as an efficient way to support increasing multicast traffic, but the enormous power losses brought by light splitting must be seriously taken into account. In this paper, we study the scheme of light-tree power recovery under optical layer power budget constraints. A modified slitter-and-delivery (MSaD) switch with the capability of power recovery is proposed. To minimize the costs and delay brought by power recovery, we develop an algorithm called optimal power recovery nodes allocation (OPRPA). Simulation results demonstrate that the power recovery scheme can guarantee power budget constraints and make the costs and delay acceptable.