Abstract: The well production of H oilfield in Middle East is positive correlation with the reservoir permeability, but the seismic wave impedance is of nonlinear relationship with the permeability. So using regular linear transform approach to convert the impedance into the permeability is only 50% in accordance rate. Cloud transform is a nonlinear stochastic simulation method, by which the functional relationship between linear deviation points and overall attribute data can be resolved. The procedures are as follows: 1) Select probability function according to the accordance rate between real data probability distribution and simulation prediction results by the function; 2) develop the cloud model for impedance?permeability conversion using the function; 3) convert the impedance into the permeability by using the cloud model. Through the cloud transform, the accordance rate for permeability prediction of H oilfield can reach more than 90%, and this method could be applied to other areas with similar geology conditions