Speech denoising is a field of engineering that studies techniques used to recover the original signal from the noisy signal corrupted with different types of noise, such as broadband noise and narrowband noise, and other types present in environment, but the spectral subtraction technique consider the most prominent in this area . In this search we will discuss the parameters impact of the modified spectral subtraction algorithm and the time window length in the enhancement of speech that corrupted with broadband noise. We done the study and determine the ideal parameters values and the ideal window length with different values for the signal -to-noise ratio SNR for noisy speech and we discuss 18 case for each value. We done the simulation using MATLAB software and the results were compared based on improving the value of SNR for each case .