Abstract: In the seed breathing CO₂ detection system, the traditional method cannot measure the concentration of CO₂ in the seed breathing in real time. According to the characteristics of seed breathing CO₂, a seed breathing detection system based on virtual instrument LabVIEW is designed based on tunable diode laser absorption spectroscopy (TDLAS). The system mainly includes laser light source and its controller, seed breathing container based on multiple reflecting pool structure. The upper computer software is mainly set with data acquisition, signal processing, concentration inversion and other functional modules, in which the concentration inversion uses the orthogonal vector phase-locked amplification algorithm to avoid the error caused by the phase difference between the reference signal and the signal to be measured. The experimental results show that the CO₂ detection system for seed respiration implemented by virtual instrument software can effectively detect the change of seed respiration, and has good anti-interference and stability, which lays a foundation for the subsequent experimental research and development.