Huber et al.[Phys.Rev.Lett.118 (2017) 200502]have proved that a seven-qubit state whose three-body marginal states are all maximally mixed does not exist.Here,we propose a method to build a maximally entangled state based on orthogonal arrays to construct maximally entangled seven-qubit states.Using this method,we not only determine that a seven-qubit state whose three-body marginals are all maximally mixed does not exist,but also find the condition for maximally entangled seven-qubit states.We consider that πME =19/140 is a condition for maximally entangled seven-qubit states.Furthermore,we derive three forms of maximally entangled seven-qubit states via orthogonal arrays.