The influences of radius-error and position-error of dielectric-rod on the properties of beam splitter,which is based on positive-negative refraction in photonic crystal,were investigated by numerical simulation with the frequency-difference time-domain method,respectively. It is found that the energy flow transmissivities of positive and negative refractive beams both remained more than 20% when the ratio of the radius-error amplitude and radius is less than 0.055 or the ratio of the position-error amplitude and lattice constant is less than 0.06.