It is a disadvantage for ballistic missile to escape interceptor having no detector to get information of interceptor. To resolve this problem, the algorithm to locate interceptor by the detection of space tracking and surveillance system (STSS) single infrared detector with the support of missile navigation information is proposed. If interceptor is captured by IR detector, it must locate in the line of sight from detector to interceptor. During the head-on interception, exoatmospheric kill vehicle (EKV) locates in the ballistic plane of penetration missile. The intersection point of detector measurement sight line and penetration missile′s ballistic plane is the position of interceptor. The feasibility that STSS infrared sensor can detect the EKV is demonstrated. Then the algorithm implement approach is expatiated and the numeral simulation of the localization algorithm is carried out. Finally, the localization error and its reasons are analyzed. It is indicated that the algorithm can provide a method for missile to locate the position of interceptor.