The present invention discloses a hematocrit detection method and detection device using the method, which is through the electrode test piece to produce a capacitor charging effect, and then uses the variation of discharge current during the capacitor discharge to detect hematocrit. The detection method includes applying a blood to a pair of detection electrodes and imposing a voltage to the detection electrodes turning off the applied voltage to obtain a discharge current value and according to a preset interpretation rule and the discharge current value to obtain an accurate hematocrit of the blood. Therefore, compared with the traditional detection method of hematocrit, the hematocrit detection method of this invention detects the discharge current during the discharge of electrode test piece, which can greatly improve the accuracy and reliability.本案揭露一種血比容檢測方法及使用該方法的檢測裝置,係透過電極試片產生電容充電效應,然後利用電容放電時所產生的放電電流變化來檢測血比容,檢測方法包括將一血液施加於一對檢測電極,並對該對檢測電極施加一電壓值;關閉所施加之該電壓值,以取得一放電電流值;及根據一預設判讀規則與該放電電流值,取得該血液之一精確血比容。如此,相較傳統血比容的檢測方式,本發明應用電極試片放電時檢測放電電流的血比容量測方法,能大幅提高精準度與可靠度。