Abstract: The traditional performance assessment method based on static statistics could not accurately describe and disclose the influence of transmission channel ionosphere to the detection ability of sky wave over-the-horizon radar. In this paper, a new assessment method based on dynamical parametric scaling has been proposed. The assessment value of radar performance is calculated with multiple weighted parameters which are the mirrors of radar ability and environment after dynamical scaling and counting. With the experimental simulation, it is demonstrated that the new method has more consistent with the real result. The value would be the evidence of radar performance and optimization, and also the support of operating parameters tuning.