An electrochemical method and a test strip for detecting hemoglobin in a specimen are provided. The method includes the steps of providing the specimen with a reagent including a buffer solution, a surfactant and an electron mediator, tetrathiafulvalene, modified by cyclodextrin; detecting electric current produced by reaction of the hemoglobin and the electron mediator in the specimen under a potentiostatic condition; and calculating a concentration of the hemoglobin in the specimen according to the detected electric current.