Abstract: In general, seismic waves for dynamic time history analysis were selected from library of analysis software. Time history analysis base force results based on these waves often don't conform to the requirements of the seismic code. NewWave software developed by author was used for correcting natural seismic waves. The software can be used to calculate response spectrum, correct natural waves acceleration time history response spectrum approximated to the seismic code and the baseline of displacement time history, etc. NewWave software can assist to choose natural waves conveniently in time history analysis.