As　Atomic　Force　Microscope　can　only　measure　the　outside　surface　of　a　capsule　in　the　Inertial　Confinement　fusion　(ICF),　a　high　precision,　non-contact,　miniaturized　Laser　Differential　Confocal　Sensor　(LDCS)　is　developed.　Based　on　the　differential　confocal　principle,　the　sensor　positions　respectively　the　test　points　on　the　outer　surface,　inner　surface　and　spherical　center　of　the　ICF　capsule　in　sequence　by　the　absolute　zero　point　of　a　laser　differential　axial　intensity　curve.　Then　it　implements　the　high-precision　measurement　of　the　ICF　capsule　by　combing　with　the　high　precision　displacement　sensor.　This　method　reduces　the　influences　of　the　surface　reflectivity　and　tilt　of　the　capsule　and　other　factors　on　pointing　characteristics　and　improves　the　anti-interference　ability.　Combining　the　traditional　microscopic　imaging　and　differential　confocal　optical　path　organically,　the　precision　pointing　is　achieved.　Theoretical　analysis　and　preliminary　experiments　indicate　that　the　axial　resolution　of　LDCS　is　better　than　5　nm,　the　standard　deviation　of　absolute　zero　is　10　nm　and　the　signal　to　noise　ratio　is　better　than　1160　when　the　Numerical　Aperture(NA)　is　0.65.　The　sensor　provides　a　new　way　for　measuring　capsules　in　the　ICFs.