[Objective] To investigate the clinical effect of shock wave on different necrotic area in patients with non-traumatic necrosis of femoral head. [Methods] The clinical information of 69 patients (101 hips) with ARCO II non-traumatic femoral head necrosis who received shock wave treatment from January 2017 to September 2018 were retrospectively collected. VAS score, Harris score and imaging were compared between the necrotic area ≤ 30% (group A) and > 30% (group B). [Results] After shock wave treatment, VAS score was significantly lower than that before treatment (P<0.05), and Harris score was significantly higher than that before treatment (P<0.05). At 12 and 24 months after treatment, VAS score and Harris score in group A were better than those in group B (P<0.001). The imaging data showed that the two hips in group A improved from ARCO II stage to ARCO I stage, and 3 hips progressed from necrotic area ≤ 30% to >30%. One hip in group B was improved from necrotic area >30% to ≤ 30% in ARCO II stage, and six hips progressed to ARCO III. No statistical significance was obsserved (P>0.05). No serious adverse reactions occurred in all patients during the treatment. [Conclusion] Shockwave therapy can significantly relieve pain and improve function in ARCO II patients with non-traumatic necrosis of femoral head. Shockwave therapy favors patients with ARCO II necrotic area ≤ 30% over ARCO II necrotic area > 30% after 6 months.