A speech intelligibility index (SII) based band importance function (BIF) for Mandarin monosyllabic words spoken by a female speaker was derived with an adaptive procedure in this work. The adaptive procedure, namely the quick-band-importance-function (qBIF) procedure, optimized the stimulus on each trial according listeners’ performance on proceeding trials in an iterative fashion. This method greatly improved the efficiency of data collection. Test-retest experiments were conducted and confirmed the reliability of this adaptive procedure at a group level. The BIF derived in this work showed generally consistence with the BIF derived with the traditional paradigm with noticeable differences at certain frequencies.