In modern days, criminal investigative techniques are growing quickly by the tremendous impact of technology . Electronic tracking device greatly promotes the capability of surveillance , but also infringes the civil rights. Though the concept of due process dominates in criminal procedural, the United States constantly expands the implication of the Fourth Amendment of "search and seizure" provisions through a series of criminal cases about location tracking. “Reasonable Expectation of Privacy” is defined as the standard of modern privacy, and the criminal justice mechanism is reviewed as the procedural safeguards, which maintain the privacy in harmony with crime control and public safety.