ImagegeometrydistortionisanimportanttechnicalstandardinB-modeultra-sounddiagnosissystem.ThispaperinvestigatesthecauseofimagedistortioninphasedarrayB-modeultrasounddiagnosissystem.Thefirstdistortioncauseisthedelayerrorofcompoundwavebind.Phasedarrayultrasoundtranduceriscomposedofmanyrectangleunits.Withcontrollinginspiringplustime,ultrasoundwave