Abstract: A method and apparatus of monitoring an ion-implantation process include a precise analysis for the process conditions of the ion-implantation process by processing the detected signals by using frequency response characteristics of plasma and thermal waves generated by irradiating an ion-implanted surface with a laser beam. The monitoring includes: counting a complex conversion coefficient from the each result value measured for the photo-thermal response by irradiating a laser beam on the sample into which ions are implanted by changing a specific process condition of the ion-implantation process; linearizing a specific parameter of complex conversion coefficient for each value of the complex conversion coefficient according to the changes of the specific process condition; and monitoring a value of the specific process condition of the ion-implantation process based on a detected value of the specific parameter which is linearized according to the changes of the specific process condition.