In this paper, shape and size of the Crack Tip Plastic Zone (CTPZ) are investigated for orthotropic materials based on Tsai-Hill and Hoffman yield criteria under various loading conditions and plane stress state for an infinite and central-cracked plate. It is assumed that the size of CTPZ is negligible verses the crack length for all loading conditions. For instance, the CTPZ is determined for orthotropic Boron-Epoxy and isotropic steel and effect of the crack’s axis angle on the CTPZ is analyzed for different loading conditions. The loading conditions were selected to obtain the CTPZ for mode I, mode II and combination of mode I and II. Dimensionless area of the CTPZ concept is used to compare the results obtained from Tsai-Hill and Hoffman yield criteria. The results show that in the same loading conditions, the size of CTPZ of Boron-Epoxy on Tsai-Hill yield criterion was smaller than on Hoffman yield criterion and this disagreement is less than the 10% and 13% based on the dimensionless area and radius of the CTPZ respectively. In a specific loading condition, the dimensionless radius of the CTPZ of isotropic materials is unique; however, it depends on the mechanical characteristics in orthotropic materials.