We carry out several numerical simulations to illustrate how the radial electric field (Er) impacts the edge magnetohydrodynamic (MHD) instabilities. The analyses reveal that Er-shear ( E r ′ , here the prime denotes the derivative with respect to the radial direction) tends to stabilize the kink / Peeling–Ballooning modes by dephasing the perturbed radial velocity ( v ̃ r ) and displacement ( ξ ̃ r ). However, Er-curvature ( E r ″ ) tends to destabilize the kink/peeling modes by inducing a phase lock between v ̃ r and ξ ̃ r . More specifically, the ratio between them could be measured to quantify their relative competition strength. Consequently, the shape of Er is crucial to the shape of linear growth rate spectrum γ (n) (here n is the toroidal mode number), which further determines the nonlinear dynamics. On the one hand, relatively larger Er-curvature causes narrower γ (n) , leading to larger nonlinear energy loss fraction. On the other hand, relatively larger Er-shear has the opposite effect. [ABSTRACT FROM AUTHOR]