The invention relates to a method for manufacturing microbridge of uncooled infrared focal plane detector and a structure thereof.The method comprises the following steps: preparing a reflecting layer on a readout circuit-based wafer;an insulated medium layer,a first sacrificial layer and a first supporting layer;etching the first supporting layer and preparing a first through hole above the reflecting layer;preparing a fist electrode,a first medium layer,a first passivation layer, a second sacrificial layer,a second supporting layer,a thermal layer and a protective layer;etching the second supporting layer and preparing a second through hole above the first electrode;etching the protective layer and preparing a contact hole above the thermal layer;preparing a second electrode, a second medium layer, a second passivation layer,a third sacrificial layer,a third supporting layer and a third passivation layer successively;releasing respective sacrificial layers to get the detector structure.With the three-layer microbridge structure,the method for manufacturing microbridge of uncooled infrared focal plane detector increases effective filling factors and makes infrared absorption more efficient.