This paper proposes a novel algorithm about image segmentation based on the vision lateral inhibition model and statistics of consecutive fields.The algorithm simulated the mechanism of the retina model of human eyes.First it picked up the variance information in the image

and then used level secant to cut the histogram from bottom to top.The algorithm counted the consecutive fields on every secant and compared each secant position and consecutive field numbers

and then made a consecutive curve.It can be proved that the secant corresponding to the curve's peak contains the boundary of the biggest consecutive field

which is the optimized threshold.The algorithm is very effective and robust.It is not only well adaptive to the change of brightness and contrast

and also can be applied to much complex background.It can improve the connectivity of strokes and lines.The result of segmentation is well coincident with the vision feeling of human eyes and the main reasons are discussed.