The invention belongs to the field of nondestructive detection, and in particular provides a welding seam eddy current detection test block. The invention also relates to a manufacturing method of the welding seam eddy current detection test block. The welding seam eddy current detection test block comprises: a first test block matrix 1, a second test block matrix 2, a welding seam 3 and a plurality of crack structures, wherein the first test block matrix 1 and the second test block matrix 2 are butt-welded, and the welding seam 3 is located between the first test block matrix 1 and the second test block matrix 2. The manufacturing method of the test block comprises: chamfering the test block matrices; butt-welding chamfers of the test block; printing the test block matrices with oil paint; processing artificial grooves. According to the welding seam eddy current detection test block and the manufacturing method thereof, the size of a true crack of a detected piece can be effectively simulated; the welding seam eddy current detection test block for eddy current detection is basically consistent with the detected piece in texture, shape, heat treatment state and surface state, and the welding seam eddy current detection test block has an artificial detect which is up to an inspection standard, and can be effectively used for setting the inspection sensitivity and evaluating the magnitude of the defect.