Forced　vibrations　resulting　from　moving　loads,　along　with　efficient　vibration　control,　are　essential　in　transportation　engineering,　earthquake　engineering,　and　aerospace　engineering.　In　this　study,　the　vibrational　response　of　an　axially　functionally　graded　(AFG)　beam　subjected　to　a　moving　harmonic　load　within　a　thermal　environment　was　investigated.　The　primary　aim　was　to　explore　the　potential　of　controlling　this　vibration　by　incorporating　a　nonlinear　energy　sink　(NES).　A　model　for　the　AFG　beam,　with　clamped-clamped　boundary　conditions,　was　developed　using　Euler-Bernoulli　beam　theory　and　the　Lagrange　method,　accounting　for　the　effects　of　the　thermal　environment　and　the　moving　load.　The　numerical　simulations　were　performed　using　the　Newmark　method　to　solve　the　governing　equations.　The　results　demonstrated　the　effectiveness　of　the　NES　in　mitigating　the　vibrational　response　of　the　beam　under　thermal　and　dynamic　loading　conditions.　The　effective　reduction　of　maximum　deflection　caused　by　moving　loads　was　set　as　the　optimization　objective　to　identify　the　most　optimal　parameters　of　the　NES.　The　results　were　presented　through　a　series　of　parameter　analyses,　revealing　that　the　nonlinear　damper　can　quickly　dissipate　the　beam＇s　energy　when　the　loads　exit　the　structure.　Furthermore,　a　properly　designed　NES　can　result　in　a　2.4-fold　increase　in　suppression　efficiency.