This paper proposes a new adaptive spectrum handoff scheme where sensor nodes opportunistically use licensed channels as long as its transmission does not cause interference with primary receivers (PRs) in cognitive radio-based industrial wireless sensor networks (CR-IWSNs). We incorporate proactive spectrum sensing into the proposed spectrum handoff scheme to reduce the number of spectrum handoff. With the proposed spectrum handoff scheme, the sensor node may still be able to access the licensed channel band even though a primary user (PU) signal is present. Moreover, a recovery spectrum handoff scheme to allow continuous connectivity between the sensor nodes under rapidly changing PU activity and efficiently recover control channel, is proposed. For the scenarios we considered, the proposed adaptive spectrum handoff outperforms the existing spectrum handoff schemes exhibiting higher throughput, reduced the number of spectrum handoff and shorter switching-handoff delay.