An improved method of boundary collocation for the problem in which the crack surface is subjected to uniform load is developed. A new stress function which is based on the stress boundary condition of crack surface is proposed. The conditions on the external boundaries are satisfied approximately by the collocation method. This improved method is applied to calculating the stress intensity factc,r (SIF) values of different angle cracks of square and circular internally cracked plates in which the crack surface is subjected to uniform normal compressive stress q, or uniform shear stress q, The new stre: s function and the calculation procedure are more convenient and simpler than other collocation techniques investigated [1, 2].