This paper discussed the Kaiser window function for following purposes: (1) briefly introduce the Kaiser window function and some of its fundamental properties; (2) proceeding from the spectrum characteristics of the Kaiser window obtained by calculation，carry out preliminary discussion and analysis on the spectrum characteristics of the Kaiser window. In this paper is given the derivation of Kaiser window formula and some parameter formulas，moreover，taking the different parameters of the Kaiser window are obtained the ratios of the energy of the function's spectra，the width of the main-lofe and the peak-values of the side-lofes，are traced the spectrum curves.