We investigate a biological model described by the following cross - diffusion system which was first proposed by n . shigesada [ 5j : this paper is concerned with the local existence and global existence of the solutions for the system ( 1 ) 我们研究的散度型方程组为:我们研究了方程组( 1 )的初边值问题解的局部解存在性和整体解存在性。