A blood detection method and a blood detection device are disclosed. When a count number of platelet in a blood sample is less than a predetermined value, a detection solution of the blood sample is prepared. A cell statistical amount of the detection solution of the blood sample is increased to obtain the platelet detection result. The cell statistics amount of the detection solution of the blood sample may be increased in an impedance detection area to perform PLT-I detection, or in an RET detection area； or performing both of RET detection and PLT-O detection simultaneously. Thus, the accuracy of platelet detection can be improved when the number of platelets in the blood sample is low.
