ObjectiveTo investigate the effectiveness of sliding trochanteric osteotomy (STO) in total hip arthroplasty (THA) for Crowe type Ⅳ developmental dysplasia of the hip (DDH). Methods Between July 2016 and April 2021, 52 patients (57 hips) with Crowe type Ⅳ DDH who underwent primary THA were enrolled according to inclusion criteria. There were 5 males and 47 females with a median age of 51 years (range, 18-76 years). There were 47 cases of single hip and 5 cases of bilateral hips. The leg length discrepancy (LLD) was 50.50 (44.00, 55.00) mm, visual analogue scale (VAS) score was 8.0 (6.0, 9.0), and Harris score was 58.0±5.0 before operation. Trendelenburg sign was positive in 46 patients (46 hips). All patients underwent STO and THA using Wagner-cone stem. The operation time, intraoperative blood loss, blood transfusion volume, Trendelenburg sign, and related complications were observed. During follow-up, VAS and Harris scores were recorded to evaluate the hip pain and function. X-ray film was used to measure the LLD and observe the bone union situations. Results The operation time was 90-125 minutes (mean, 105 minutes). Introperative blood loss was 420-800 mL (mean, 640 mL). Ten patients underwent blood transfusion and the amount of allogeneic blood transfusion was 2-4 U (mean, 3 U). All incisions healed by first intention after operation. All patients were followed up 4-60 months (median, 24 months). At last follow-up, LLD was 6.00 (4.00, 7.75) mm, showing significant difference when compared with that before operation (Z=−6.278, P=0.000). After operation, 51 hips (89.5%) achieved bone union at the osteotomy site, 4 hips (7.0%) had fibrous union, and 2 hips (3.5%) had nonunion. The healing time of osteotomy was 3-12 months, with an average of 6 months. At last follow-up, the VAS score was 3.0 (2.0, 5.0) and the Harris score was 85.0±6.0. The differences between pre- and post-operation were significant (Z=−6.176, P=0.000; t=−25.285, P=0.000). Trendelenburg sign remained positive in 4 patients (4 hips) at last follow-up and the difference was significant when compared with preoperative (χ2=67.947, P=0.000). One patient had a medial femoral cortical fracture when Wagner-cone stem was implanted during operation, and 2 patients had early symptoms of sciatic nerve palsy after operation, and no other related complications occurred. Conclusion For Crowe type Ⅳ DDH patients, STO applied in THA can reduce the resected bone mass, provide better exposure of hip as well as improve function of hip abductor muscle. Wagner-cone stem is recommended.