This paper addresses a mode I dynamic crack tip singular stress field based on an isolated moving edge dislocation elastic stress field for MEMS structural design. The crack tip singular stress field was derived by applying the Eshelbian eigenstrain and Fourier transform method. The large normal stress component of the crack tip singular stress appeared as the crack velocity increased up to the Rayleigh sonic speed. Therefore, the principal stress plane of the fast-moving crack tip deviates from the original mode I crack plane, which can initiate crack kink or bifurcation.