The invention relates to the field of control for compressors, and discloses a control method and device for performance of a PCL compressor. The control method comprises the steps of generating practical machine core data of the PCL compressor through acquiring the performance test data of a centrifugal compressor and carrying out physical properties computation and performance iteration of actual gases; selecting the machine core of the compressor requiring to be calculated, inputting the field flow, inlet pressure, temperature, components and rotation speed, and calculating the practical performance of the compressor; calculating to generate a curve and/or table according to the practical machine core data, and acquiring an optimal performance point under the field condition according to the curve and/or table; and marking the practical performance of the compressor on the curve and/or table as a current performance point, and adjusting and controlling the compressor to operate in an efficient zone according to the difference between the current performance point and the optimal performance point. According to the control method, errors caused by calculation through adopting an expectation curve are eliminated, the result is accurate, and the deviation caused by approximate and similarity transformation is eliminated.