Great attention has been paid to calculating conveniently the electromagnetic field due to a loop antenna buried in stratified media. It is quite difficult because this topic is involved with the computation of Sommerfeld-Type integral. In this paper the closed-form expressions of far field of a loop antenna in a three-layered conducting medium are obtained rapidly by using a new technique to evaluate Sommerfeld-Type integral with the aid of the complex image theory. The present approach can be also used to get the far field formulas of other similar cases.