Deterministic　secure　quantum　communication　(DSQC)　is　an　important　branch　of　quantum　cryptography　and　has　attracted　continuous　attention.　However,　in　practical　DSQC,　the　receiver＇s　detectors　can　be　subjected　to　detector-side-channel　attacks　launched　by　the　outside　eavesdropper.　Moreover,　encoding　the　information　in　only　one　degree　of　freedom　(DOF)　of　photons　makes　DSQC　inefficient.　Here,　to　remove　all　the　detector　side　channels　and　increase　single-photons＇　channel　capacity,　we　report　the　first　high-capacity　measurement-device-independent　DSQC　(HC-MDI-DSQC)　protocol　by　using　photons＇　polarization-spatial-mode　DOFs.　This　method　is　similar　to　the　idea　of　MDI　quantum　key　distribution.　Theoretical　analyses　show　that　it　is　advantageous　in　terms　of　security　and　efficiency　compared　with　the　state-of-the-art　DSQC　protocols.