Deterministic　secure　quantum　communication　(DSQC)　is　an　important　primitive　of　quantum　cryptography　and　has　attracted　continuous　attention.　Here,　we　report　the　first　DSQC　protocol　based　on　spatial　encoding.　The　qubit　information　is　encoded　in　the　spatial-mode　degree　of　freedom　of　photons.　A　decoy　state　technique　is　used　to　ensure　the　security　of　the　DSQC　protocol.　We　also　analyze　the　security　of　the　DSQC　protocol　and　show　that　it　is　secure　against　common　attacks　such　as　the　interception-and-retransmission　attack　and　general　entanglement-measurement　attack.　Without　the　use　of　the　polarization　state　of　photons,　it　avoids　the　degeneration　of　the　states　of　photons　so　that　it　is　suitable　for　long-distance　quantum　communication.