We study the statistical behaviour of the tracer motion between two lines in two-dimensional percolation porous media,based upon the direct numerical solutions of the Stokes equations on 20000 different percolation structures.At the critical threshold p = pc,the travelling length has an exponential distribution rather than a power-law distribution.Numerical simulations show that the ensemble average travelling length 〈l〉～ L1.21 and 〈l〉～ L for p = pc and p ＞ pc,respectively.The region of the tracer dispersion is wide when p = pc and rather narrow when p ＞ pc.Numerical simulations indicate that the transverse fluctuation has the same scale as the correlation length of the percolation structure,which is a system of size L when p = pc and is constant for a large system size L when p ＞ pc.It is also shown that the travelling time has a power-law behaviour when p = pc.