Purpose: To explore the method and probability for directly measuring the stress in lumbar facet joint and disc under dynamic loading, to afford the experimental base for further investigation of intra-articular stress changing regularity under different motion conditions. Methods: Using micro pressure-sensitive crystal sensor and long lumbar segment, to collect, transform and analysis the signal under six status. To analysis and test the features of signal and experimental instrument. Results: We get complex and non-periodic instant signal. The characteristic of whole instrument is only collecting dynamic signal. high sensitivity, large responsive frequency range. high stability and high repetition. Conclusion: This is a kind of new and practical biomechanical research method. It more directly and really express the intra-articular stress change.