Molecular dynamics simulations are carried out in this report to study the dynamic fracture behaviors of single crystal aragonite. Two typical edge and central model I cracks that along [010] and [100] directions, respectively, are introduced to the aragonite plates. Our simulation results reveal that (110) and (010) planes are the preferable cleavage planes for crack propagation in aragonite, which is in good agreement with the experimental observations. Brittle and ductile fracture behaviors are identified when the applied tensile loadings are along [010] and [100] directions, respectively. Zigzag crack propagation path, i.e., crack deflections, is observed in the uniaxial tension simulation of the models with [010]-oriented cracks. Overall, the cracks prefer to propagate along (110) plane. Stable nonlinear crack growth and the following unstable crack propagation are identified through analyzing the crack growth resistance. For the case with [100]-oriented crack, straight propagation path and flat (010) crack surfaces are revealed after the fracture of aragonite.