Abstract: In order to understand the seismic ground respons e of Taipei Basin, a series of field and laboratory dynamic soil tests have been performed in the l ast ten years. A method of adjusting the laboratory test results to reflect the in site soil conditions and an optimization technique to identify the unique par ameter from hundreds data were studied. Some PGA of seismic ground response reco rds were then used to testify the precision of the proposed method and parameter s.