The structure of GH4169 is so complex that it is difficult to be evaluated accurately with a single ultrasonic parameter. However, the multi-parameter ultrasonic evaluation (MUE) method has a problem in selecting a reasonable parameter set. Therefore, a new full-parameter ultrasonic evaluation method is proposed to introduce quasi-circular mapping into evaluation. All ultrasonic parameters are projected into the space of a two-dimensional circle. A projection polygon is constructed, and the second-order features with global ultrasonic information are extracted. Then the high-order polynomial fitting is carried out with the grain size, and the evaluation problem is transformed into an optimization problem with minimum fitting error and quasi-circular mapping parameters as design variables. Finally, the grey wolf optimization is used to solve and obtain the final all-parameter ultrasonic evaluation model. The experimental results show that compared with other ultrasonic evaluation methods, the new method has the characteristics of high accuracy and good robustness.