Post fiber, core, and crown restorations in post-endodontic treatment using ferrules strengthen teeth after post-restoration. To investigate the effect of different ferrule height designs on the resistance of dental fractures following endodontic treatment, using AUTOCAD as the basis for non-linear finite element analysis. Five models of 3D maxillary first incisors were constructed using AutoCAD 2016 with five different ferrule heights (mm) 0, 0.5, 1, 1.5, and 2, meshing and input mechanical properties, followed by loading 25 N and 170 N at an angle of 135° in the tooth palatal area which was analyzed by Finite element analysis (FEA) using ANSYS v 17.0 software. Von Mises analysis shows the maximum and minimum deformation values, equivalent elastic strain, and equivalent stress. The ferrule's total deformation value in the 25 N simulation was the highest at 0 mm (0.0093 mm) and the lowest at 2 mm (0.0091 mm). The simulation load was 170 N, the highest at 0 mm (0.0632 mm) and the lowest at 2 mm (0.0618 mm). The maximum equivalent elastic strain value of ferulle is highest at 1 mm (0.034814 mm) and lowest at 0 mm (0.03245 mm). The maximum equal stress value decreases in models with ferrules. In the 25 N and 170 N simulations, the highest values on the 3D model are at 0 mm (13,008 MPa and 88,452 MPa) and the lowest at 1 mm (11,567 MPa and 78,655 MPa). Conclusion.The addition of ferrule height can increase dental fractures' resistance after endodontic treatment by reducing deformation. Ferrule decreases stress on the tooth's labial cervical area and enlarges the strain on the cervical palatal dentine by holding non-axial loads from the palatal side.