Abstract: Parameters on ionospheric irregularity are essential for scintillation modeling. As scintillation is generally observed on a single site basis, it had been a hard work to retrieve various irregularity parameters. However, development of scintillation theory model provides a possible solution to this difficulty. Here we present a new method to estimate irregularity parameters with maximum likelihood estimation (MLE) based on scintillation spectrum fitting. Quality of the method is verified with Monte Carlo simulation. It shows that an unbiased optimal estimation could be achieved for single spectral index model with all results located within the 90% confidence interval, while a near unbiased optimization could be reached for double spectral index model with most of results in the 90% confidence interval. Statistic distribution of estimation results follows the theoretical one well, showing the viability of estimation. Test is also conducted with real measurements and the result is promising. Two kind of data tests show the method could work efficiently under modest and strong scintillation conditions. This would pave the way for scintillation modeling with commonly observation on single site.