In order to study the detonation velocity deficits of wound mild detonation cords, a physical model and a theoretical mathematical equation for detonation velocity deficits of wound mild detonation cords were established based on the detonation waves corner effects and delay time phenomenon by using non-dimensional analysis method. Besides, a semi-empirical formula for detonation velocity deficit of wound mild detonation cords in the same charge size was obtained through experiments and curve fitting. Both the theoretical mathematical equation and the semi-empirical formula show that the detonation velocity deficit of wound mild detonation cords and the reciprocal of the curvature radius have an exponential relationship.