The present invention provides an electrochemical method and a test strip for detecting hemoglobin in a specimen. The method includes the steps of providing the specimen with a reagent, which has a buffer solution, a surfactant and an electron mediator, tetrathiafulvalene, modified by cyclodextrin; detecting electric current produced by the reaction of the hemoglobin and the electron mediator in a specimen under a potentiostatic condition; and calculating a hemoglobin concentration in the specimen according to the detected electric current. In the method of the present invention, tetrathiafulvalene modified by cyclodextrin is used as an electron mediator, which directly interacts with the hemoglobin in the specimen. Since the hemoglobin concentration is in inverse proportion to the value of electric current or the value of SOC (state-of-charge) integrated by electric current value with time, the hemoglobin concentration in a whole blood specimen or the hematocrit level in a blood specimen is accurately and rapidly obtained according to the detected electric value or the value of SOC.