Square spiral inductors are designed with EM program in accordance with the inner diameter and the metal thickness which is 0.2.mu.m and 20.mu.m respectively. We propose a parameter extraction method based on the S-parameter. Lumped equivalent circuits of spiral inductors are analyed with reflection coefficient S$_{11}$, of witch freqency rnage is 1~10GHz. When metal thickness is 0.2.mu.m, S$_{11}$ with EM simulation is not the same as S$_{11}$ that of SPICE simulation. So we suggests a new lumped equivalent circuits which compensate circuits. Te new lumped equivalent circuits are adequate for other inductor with small scale at high frequencies.ncies.