The effectiveness of objective evaluation indicators for sound quality varies with the evaluation object and application scenario. Traditional objective evaluation parameters mainly focus on time domain features, which is difficult to effectively characterize howling and harsh features. To address these issues, the frequency domain derived feature parameters of tonetonoise ratio(TNR) and prominence ratio(PR) were constructed. The objective evaluation system of sound quality was improved by combining time and frequency domain features. The proposed objective parameters of diesel engine have higher prediction accuracy with MSE of 0.015 3 and R² of 0.981 9 compared to the traditional objective parameters.