Unextendible maximally entangled bases in ${\mathbb{C}}^d⨂{\mathbb{C}}^{d^{\mathrm{\prime }}}$

We solved the unextendible maximally entangled basis (UMEB) problem in ${\mathbb{C}}^d⨂{\mathbb{C}}^{d^{\mathrm{\prime }}}(d\mathrm{\ne }{d}^{\mathrm{\prime }})$,the results turn out to be that there always exist a UMEB.In addition,there might be two sets of UMEB with different numbers.The main difficult is to prove the unextendibility of the set of states.We give an explicit construction of UMEB by considering the Schmidt number of the complementary space of the states we construct.