Abstract: Objective To analyze the indications of Onlay island flap urethral plasty in children suffered from hypospadias and the prevention and treatment of its complications. Methods Seven children with hypospadias admitted to our department from March 2010 to June 2016 had undergone Onlay island flap procedure.The clinical data were analyzed retrospectively. Results The average age of the 7 children was 4.32 years(ranging from 1.5 to 8 years).Of the 7 cases, primary procedure was performed in 6 cases, and 1 case received reoperation for chordee, fistula and subcoronal meatus after straightness of penile and urethroplasty at another hospital.Preoperatively, 1 case showed small glan with diameter of 0.8 cm, and 3 glans were flat and absent of clonical configuration with diameter of 1.0 cm.All patients presented with various degree of chordee, 2 of them accompanied with penile torsion counterclockwise.Through releasing of the skin and dartos fascia of 6 patients who received one-stage surgery, 4 patients obtained straightness of penile, and the other 2 cases presented with slight chordee adjacent to the coronal site.One patient with reoperation presented with glan chordee.After completely correction of chordee, the meatus were at the connecting sites of subcoronal, proximal penile and penoscrotal with the absent sizes of urethra 1.5-4 cm and mean size 2.64 cm.Urethral plate presented with certain degree of depth and stretched with good blood supply.The interval sizes of island flap of inner prepuce for urethroplasty were 0.5-1.0 cm, with a mean value of 0.7 cm.All patients achieved straight peniles and good urine diversion without urethral stricture.Five patients had no fistula, while 1 case presented with island flap necrosis and blood exudation of glan with the meatus located on the penoscrotal.The one who received reoperation showed subcoronal fistula with dripping state, and 1 patient presented with incision fissure of ventral prepuce without fistula. Conclusion Onlay island flap procedure is fit for patients with the following pathological anatomy, including the urethral plate has certain depth and ductibility, which will not stretch the ventral of penis, or it may slightly stretch the ventral of penis which can easily be corrected by Tunica albuginea plication.After completely correction of chordee with corpus spongiosum presented adjacent to meatus, the meatus may locate at the connecting sites of subcoronal, penile or penoscrotal.The depth of incision of glans and urethral plate and effective hemostasis are essentials for this procedure.