A method to design an arbitrary-geometty(0,π)model binary phase grating isproposed after we have analyzed and compared the characteristics of all kinds of codingschemes.The development of this method can be divided into two steps:firstly,to get thehighest diffraction efficiency,we find the initial binary phase structure,secondly,we adoptan iterative method to optimize above initial structure to get expected intensity dispersion.We have designed 7 binary phase gratings to split the incident light beam into equal-intensity beams. Their diffraction efficiencies are all above 80% and their uniformity deviations are all below 0.01%, which are better than other reported results to the best of our 1< knowledge.