Objective: To explore the correlation among paraspinal muscle functions electromyography (EMG), muscle stiffness, and pain threshold in patients with adolescent idiopathic scoliosis (AIS). Methods: Eighteen patients with AIS were recruited. A Noraxon system equipped with four wireless EMG sensors was used to collect EMG data on the paraspinal muscles in relaxed standing and weight-bearing standing states. Muscle stiffness and pain threshold were measured using a muscle tonometer. The differences in mean EMG amplitude, muscle stiffness, and pain threshold between the concave and convex sides of the scoliosis were analyzed. Results: Among patients with different scoliosis locations, Cobb angles, ages, and brace treatment durations, the mean EMG amplitude of the paraspinal muscles on the convex side of scoliosis was significantly higher than that on the concave side (P<0.05). The muscle stiffness and pain threshold of the paraspinal muscles on the convex side were also significantly higher than those on the concave side (both P<0.05). There was a low correlation between the mean EMG amplitude of the paraspinal muscles, muscle stiffness, and pain threshold (R<0.5, P>0.05). Conclusion: In AIS patients, the electromyographic activity, muscle stiffness, and pain threshold of the paraspinal muscles on the convex side of scoliosis were all higher than those on the concave side, and the correlation among the three indicators was low.