In order to solve the multicast tree establishment problem for multi -domain ASON,an impairment-aware multicast routing algorithm based on hypergraph model is pres ented.In the presented algorithm,a new multi-domain hypergraph model is firstly proposed.In conside ration of the constraints of physical or attack impairments,the strategy of K paths a nd the method of the establishing inter-domain hyper-tree based on hyper-path are used respectively.Meanwhile,an example a nalysis was carried out.This algorithm not only finish the multi-domain multica st routing and wavelength assignment, but also has the lower time complexity. The experimental results show that the proposed multicast routing algorithm i s effective and can achieve good average blocking performance by measuring the effect of the K value,the multicast size,the wavelength number and distribution strategy,and the number of domains on the network average bloc king probability.At the same time,the actual multi-domain multicast size should be proportional to the numb er of the domains which is also suggested.