Abstract: We developed a portable non-specific low back pain measurement system EasiLBP and evaluated its performance in collecting EMG signals:during the wearer's movement without the assistance of a doctor, the collection of EMG signals by portable devices met problems such as large noise interference, difficulty in accurately calibrating the start and end points of the action interval, and imbalanced samples for feature recognition, et al. To challenge these problems, we proposed a small group-based noise removal method, a dynamic dual-threshold automatic method for identifying the start and end points of the motion interval, and a sampling method to balance group samples, respectively. Portable device and a medical EMG acquisition equipment Thought Technology FlexComp Infiniti 10 were used to perform EMG measurements on 15 patients with non-specific low back pain and 15 normal people. Clinical experiments and statistical analysis show that the portable EMG acquisition system has significant differences in EMG signal characteristics between normal people and non-specific low back pain patients, and it has good measurement consistency and accuracy with the medical EMG acquisition equipment.