In order to improve the security and accuracy of information transmission for fiber optic sensor nodes, a fiber optic sensor node information secure transmission technology based on NB IoT technology is proposed. Construct a NB IoT channel structure model for information transmission of fiber optic sensor nodes, use carrier activation modes (SAPs) to achieve carrier modulation and anti-interference suppression during the information transmission process of fiber optic sensor nodes, construct a hybrid mapping scheme to achieve secure mapping encryption design during the information transmission process of fiber optic sensor nodes, and introduce index modulation technology into the orthogonal frequency division multiplexing system for fiber optic sensor node transmission, Combining parity check to achieve channel allocation and transmission bit rate localization detection for fiber optic sensor nodes. The simulation results show that the proposed method has better security and encryption performance in the information transmission of optical fiber sensor nodes, the maximum transmission prediction error is only -2.0, and the transmission bit error rate is the highest 0.20×10-10, the average is only 0.17×10-10, and when the anti-interference ability is tested, the signal-tonoise ratio of this method reaches more than 49.8 dB, which improves the transmission stability and anti-interference ability of optical fiber sensor nodes.