Models beyond the Standard Model have been proposed to simultaneously solve the problems of naturalness and neutrino mass, in which heavy Majorana neutrinos and vector-like top partners are usually predicted. A new decay channel of the top partner mediated by the heavy Majorana neutrino can thus appear: $Tto b,W^{+}to b,ell^{+}ell^{+}qbar{q}$. We study in this paper the observability of this decay process through single production of the top partner at the 14 TeV LHC: $ppto T/bar{T}$+jets$to b/bar{b}+mu^{pm}mu^{pm}$+jets. $2sigma$ exclusion bounds on the top partner mass and mixing parameters are given by Monte-Carlo simulation, which surpass those from the search through VLT pair production in the mass range of $m_{T}>1.3$ TeV.