1. A computing system for measuring a border of an image of an object, comprising: a parameter setting module operable to set measurement parameters of the object, the measurement parameters comprising a length of a measurement line and a sampling interval of the object to determine accurate border points of the object; an image focusing module operable to select a start point, an end point, and an image captured direction of the object to capture an image of a border of the object, assign a variable “isS” with a value of “true” if an image of the object is the first captured image, and setting the start point as a current point of the object; the image focusing module further operable to move a charge coupled device (CCD) lens of an image measuring machine to the current point; an image processing module operable to capture an image of the object, perform binary image processing on the border of the captured image to obtain a binary image, and obtain sequential border points in the binary image; the image focusing module further operable to determine if the sequential border points in the binary image are fuzzy, and perform an automatic focus function on the border of the object if the sequential border points in the binary image are fuzzy; a border measuring module operable to determine if the border of the object has been completely captured, and displaying success information if the border of the object has been completely captured; the border measuring module further operable to calculate accurate border points according to the length of the measurement line and the sampling interval if the border of the object has not been completely captured, select a last point from the accurate border points as a new start point to capture a next image of the object, determine a position of the CCD lens according to the new start point, mark isS=false if an image of the object is not the first captured image, and set the new start point as the current point, then capture the next image of the object to measure; wherein the image focusing module determines if the sequential border points in the binary image are fuzzy comprises: sampling a preset quantity of border points from the sequential border points; calculating an average value of grads of the sampled border points; and determining the sequential border points are fuzzy if the average value of grads is less than a preset value.