In this paper, a tracking algorithm called "ratio method" is introduced for intelligent vehicle competition electromagnetic group. The conventional tracking algorithms including "difference method" and "normalization method" have problems. For instance, there are extreme points in the function of deviation value and deviation distance, what is worse, the relation between them will change into negative correlation outside two extreme points. To solve this problem, the ratio method changes the electromotive force values into the ratio of the difference and the sum of respective square root electromotive force values. It turns out this tracking algorithm could remove the extreme points, besides the relation between electric potential difference and deviation distance maintains positive correlation within the entire value range, so as to eliminate misjudgment. After experimental verification, the results using this tracking algorithm are more effective than other conventional tracking algorithms. This paper solves a practical problem appearing in intelligent vehicle competition