A testing structure of a strip width of a scribing slot is provided, the structure includes a first isolated line (232) and a second isolated line (234) which are perpendicular to each other, the testing structure further includes a first field region pattern (220), the first field region pattern (220) includes two graphics, the two graphics are each located on one side of the first isolated line (232) and opposite to each other. A testing method of a strip width of a scribing slot is also disclosed. Graphics of the field oxide region simulating the LOCOS structure are provided on two sides of the isolated line, the step is artificially generated, a polysilicon gate graphic on a small size source region formed by photolithography can be displayed through online testing of the strip width or online displaying and checking of the strip width, thus a practical situation of the die can be known, an abnormity of the strip width and morphology of the polysilicon gate caused by a reflection of a substrate can be found instantly.