•Scutellaria baicalensishas reversal effect on radio-resistance of colorectal cancer (CRC).•Wogonin is the main active component of Scutellaria baicalensis.•SULT2B1 is highly expressed in CRC and associated with poor prognosis.•Wogonin could increase the radio-resistance sensitivity of CRC.•Wogonin reverses radio-resistance in CRC by targeting SULT2B1.