Orbital Anomaly of space object is an important problem for satellite operators and users. It is very meaningful to find orbital anomaly timely and quickly. By analyzing orbital anomaly of space objects, the avoidance or collision event can be found and discriminated, further the ability of United States Space Surveillance Network (SSN) can be determined. This paper put forward a simple orbital anomaly analysis method based on TLE data called Semi-major Axis Change Method (SACM). This method is rapid and valid, and can be applied to orbital anomaly analysis of LEO operational satellites and the breakup debris produced in the Cosmos 2251 and Iridium 33 satellite collision. With this method, the discrimination accuracy rate can reach 100 percent. By analyzing the orbit anomaly of American Russian breakup debris with SACM, it is found that US SSN can steadily detect over 90 percent breakup debris.