One of the main problems in the classical methods for analyzing crack is a discontinuity in materials and specific conditions at the crack tip. Existing computational methods for the modeling of fracture in a continuous body are based on the partial differential equations of classical continuum mechanics. These methods suffer from the inherent limitation that the spatial derivatives required do not exist at crack tips or along crack surfaces. To overcome this problem, Peridynamic theory (PD), which has been introduced in recent years, could be used to improve the analysis of cracked structures. In the present paper the crack growth and propagation in an inclined crack in the plate is studied. The governing equation is developed and solved using Peridynamic theory and the results are validated using other investigations. Effects of various pre-crack angles and speeds of load application are studied. As it will be illustrated, the PD theory can reasonably model an inclined crack growth and predict the complex phenomenon of crack linear growth or crack branching at various conditions of applying loads. In addition, the results show that the amount of crack growth can be increased by increasing the rate of loading.