In　this　paper,　the　key　technology　of　interferometric　microwave　thermometer　is　studied,　the　research　can　be　applied　to　the　temperature　measurement　of　human　body　and　subcutaneous　tissue.　This　paper　proposes　a　hardware　architecture　of　interferometric　microwave　thermometer　with　2　GHz　bandwidth,　in　which　the　phase　shifter　is　used　to　correct　phase　error　and　the　quadrature　demodulator　is　used　to　realize　autocorrelation　detection　function.　The　results　show　that　when　input　power　is　7　dBm,　the　detection　sensitivity　can　reach　176.54　mV/dBm　and　the　temperature　resolution　of　the　microwave　radiometer　can　reach　0.4　K.　Correction　algorithm　is　designed　to　improve　the　accuracy　of　temperature　measurement.　After　correction,　the　phase　error　is　reduced　from　40°　to　1.4°　and　when　temperature　changes　0.1　°C,　the　voltage　value　changes　obviously.　Step-by-step　calibration　and　overall　calibration　are　used　to　calibrate　the　device.　Inversion　algorithm　can　determine　the　relationship　between　physical　temperature　and　output　voltage.　The　mean　square　error　of　water　temperature　inversion　by　multiple　linear　regression　algorithm　is　0.607　and　that　of　BP　neural　network　algorithm　is　0.334.　The　inversion　accuracy　can　be　improved　by　reducing　the　temperature　range.　Our　work　provides　a　promising　realization　of　accurate,　rapid　and　non-contact　detection　device　of　human　body　temperature.　©　2021　by　the　authors.　Licensee　MDPI,　Basel,　Switzerland.