Semiconductor laser is one of the core light sources of optical fiber communication systems. Better semiconductor laser performance helps to increase the capacity and quality of the entire fiber optic communication system. In order to design better semiconductor lasers, it is often necessary to simulate various performances through rate equations. However, some parameters need to be obtained through experimental results, so it is necessary to fabricate semiconductor laser chip to extract the parameters. Through multiple rounds of iterative experiments and theoretical calculation, chip optimization is continuously carried out to achieve the final goal. In the process of optimization analysis, in order to better analyze the performance of laser chips, laser parameters are usually divided into eigen parameters and parasitic parameters. Parasitic parameters mainly include capacitance, resistance and other properties. They can be obtained by means of a fitting method by combining a reflection curve of the small-signal frequency response (S₁₁) with an equivalent circuit model. These parameters are basically not affected by the laser-current change. However, the extraction of the eigenmetric parameters is related to the selected laser-current range, and the parameter extraction results themselves have a variety of possible answers. How to obtain more accurate and suitable for a wide operating current range of eigen parameters is the focus of this paper. In recent years, with the development of emerging applications such as 5G optical communication and Radio On Fiber (ROF) analog communication, semiconductor lasers are required to operate at larger drive currents to improve high-speed performance and are required to have better linearity. In such ROF analog communication systems, semiconductor lasers need to work at a lager bias laser-current and in the linear region to obtain excellent microwave performance. Besides, it is need to test and evaluate many microwave performance indicators, such as third-order intermodulation, second harmonic, relative intensity noise, etc. The acquisition of these indicators requires complex test systems, expensive equipment and difficult testing. Therefore, how to accurately and conveniently obtain the microwave performance of the laser at a large drive current is particularly important. By testing some basic performance of the laser, the eigenvalue and parasitic parameters of the semiconductor laser can be extracted. These extracted parameters, combined with system characteristics, can be used to quickly calculate and evaluate most of the microwave performance of the system. This method greatly reduces the test requirements and the costs of test equipment, greatly speeding up the performance evaluation of semiconductor lasers and the entire design process. The traditional parameter extraction method can obtain the parameter values of semiconductor lasers operating at low bias currents (10~40 mA). But the parameter extraction at large currents is not very accurate, and more complicated tests such as measuring chirps are required. This paper re-evaluates the applicability of approximate conditions in common semiconductor laser parameter extraction methods and finds that approximate conditions fail at large currents. To this end, it is proposed to use a more general formula for the parameter extraction of the semiconductor laser rate equation. Taking the DFB laser chip as an example, the small-signal frequency response curve (S₂₁) is used to accurately extract the resonant frequency f_r and the damping factor γ of the semiconductor laser, and combined with the laser power-current (P-I) response curve of the laser, the various parameters of the semiconductor laser rate equation can be calculated. Compared with the previous parameter extraction approximation calculation method, the present method has three advantages. First, the range of laser drive currents that can be analyzed is wider. Second, there are fewer items to test. The third is that the extraction of parameters such as the resonant frequency f_r at large currents is more accurate. This method is an important reference for the optimization and improvement of semiconductor laser with wide operating currents such as analog laser.