In order to study the characteristics and the influence factors of the parameter estimation of Neyer D-optimal sensitivity test,the effects of the initial guesses of parameters and the sample size on the precision of parameter estimation were studied by computer simulation. Results show that the mean estimation is unbiased; about one-third of the standard deviation estimation is smaller and two-thirds of the standard deviation estimation is bigger; the initial guesses of the parameters have a little effect on the precision of parametric estimation; a better mean estimation can be obtained if sample size is more than 18.