Abstract: Two sample tubes with different depth-width ratio of cracks were designed to investigate the detection sensitivity of array eddy current to the cracks with different depth-width ratio. Array eddy current testing method was used to detect and compare the defects of the sample tubes. The results show that according to the study of the characteristic parameters of the crack depth-width ratio, when the crack width is constant and the depth-width ratio is greater than 1, the eddy current amplitude gradually increases with the ratio rising. When the crack width is constant and the depth-width ratio is smaller than 1, there is no obvious correspondence between the eddy current amplitude and the ratio. When the crack depth is constant and the depth-width ratio is greater than 1, the eddy current amplitude gradually increases with the ratio rising. According to the study of depth-width ratio with the same width but different depth, and the same depth but different width, when the depth-width ratio is constant, the eddy current amplitude of the simulated crack detected by the array eddy current gradually increases with the detection frequency rising.