The invention provides an integrated miniature flat plate type atmosphere fine particle spectrum measurement device. The device comprises a unipolar flat plate charged module, a particulate matter grading and inversion module and a micro-current detecting and signal processing module, wherein the unipolar flat plate charged module mainly comprises a first upper panel, a first lower panel, insulation blocks, a charged lower electrode, needle tips, a unipolar high-voltage power supply and a sheath gas inlet; the particulate matter grading and inversion module mainly comprises a first slant plate, a second slant plate, a second upper panel, a second lower panel, an intermediate washer, sound nozzles, symmetric sample gas inlets, laminar flow sheets, an upper separation electrode, a lower separation electrode, a classified sample gas outlet, a Faraday cup, a first sensitive electrode and a second sensitive electrode; the micro-current detecting and signal processing module mainly comprises a controller, a scanning voltage module, a vacuum pump and a vacuum pump drive module and a micro-current detecting device. The invention further provides a measurement method adopting the integrated miniature flat plate type atmosphere fine particle spectrum measurement device. The integrated miniature flat plate type atmosphere fine particle spectrum measurement device and the measurement method have the advantages that the structure is simple, integration can be realized, and technical support is provided for on-line measurement by miniaturized handheld atmosphere fine particle spectrum measurement instruments.