A　novel　weight　sensor　based　on　the　Michelson　interferometer　is　proposed　in　this　study　to　meet　the　demands　of　complex　environments.　The　sensor　uses　a　dual-beam　type　elastic　element,　optimized　to　enhance　its　sensitivity.　Its　deformation　under　load　is　sensed　by　a　broadband　optical　coherence　displacement　measurement　system,　which,　in　combination　with　the　spectrum　correction　method,　enables　displacement　sensing　down　to　sub-nanometer　res-olution.　An　optical　interferometric　weight　sensor　with　a　rated　load　of　6　kg　is　fabricated　under　laboratory　con-ditions,　and　its　performance　is　verified　experimentally.　The　proposed　weight　sensor　demonstrates　good　stability　and　achieves　a　sensitivity　of　146.814　mu　m/kg,　theoretical　resolution　of　0.004　g,　nonlinearity　error　of　0.034%,　maximum　repeatability　error　of　0.036%,　and　maximum　hysteresis　error　of　0.055%,　with　the　relative　error　of　the　identification　threshold　not　exceeding　0.1%.　The　proposed　weighing　method　and　sensor　represent　a　significant　improvement　over　other　reported　interferometer-type　weight　sensors.