High rate non-Darcy flow increases additional pressure drop and decreases flow efficiency in reservoirs, which is unfavorable to petroleum production.Whether high rate non-Darcy flowis easier to occur in low permeability reservoirs or in high permeability reservoirs is a problem unsolved well. Previous experiment results by several authors showthat low permeability reservoirs are more suitable for high rate non-Darcy flowto occur. However flowin low permeability reservoirs is extremely difficult and high rate can not be reached usually. According to mechanics of fluids, conditions of high rate non-Darcy flow and factors causing high rate non-Darcy flow were studied. It is considered that high rate non-Darcy flowis easier to occur in high permeability reservoir than in low permeability reservoir. So the effect of high rate non-Darcy flowcan be neglected in development of low permeability reservoirs.