In order to know the influence of impacting pose on the sound discreteness of a single pistachio , the sounds of the closed and open pistachio during impacting were recorded, and the 100-times data for each type on the same condition were analyzed including the discreteness of spectrum and statistical parameter. The discreteness of spectrum was evaluated by the angular separation between each sample signal with its average and variation coefficient, ant that of statistical parameter was then assessed by its variation coefficient, represented by energy, entropy and zero-cross rate, respectively. Moreover, the variation coefficient of the parameter was defined as the standard deviation over the average. The results were demonstrated as follows. Firstly, we found that for the open pistachio, angular separation was 30.94°, and the variation coefficient was 16.56%. What is more, the statistical parameter’s variation coefficient were 38.33%, 2.30%, 20.00%, and its average were 11.20, 4.39, 63.43 for energy, entropy and zero-cross coefficient, respectively. Sencondly, it was found that, for closed pistachio, the angular separation was 20.52°, the variation coefficient was 25.11%, the statistical parameter’s variation coefficient were 18.36%, 2.27%, 13.08%, and its average were 6.08,4.28,62.94 for energy entropy and zero-cross coefficient, respectively. Thus we could get the conclusions that the random impact pose could have an influence on impact sound signal discretely.Furthermore, the discreteness of open pistachio was higher than the closed ones. Lastly, The random impact pose was also found making spectrum and statistics parameter discretely in a limit range, so it was possible to sort open and closed pistachios using the parameters of larger differences on average whereas smaller value on variation coefficient.