Abstract: The horizontal columns, in which tracers and undisturbed soil collected from the aquifer are filled, are inserted into the aquifer through the experimental shaft wall. Natural underground water flowing through the horizontal columns is collected in sample bottles. The tracer concentrations in both water and soil samples are obtained. The retardation coefficient of 90Sr, which migrates at fastest velocity among tracers, is more than 290, so loess has stronger capacity to sorbs the nuclides of 90Sr, 237Np, 238Pu and 241Am; retardation coefficient of 90Sr in the horizontal columns 3 and 8 with humus are larger than those in the horizontal column 2 without humus. It shows that humus may retard migration of 90Sr. And retardation coefficient of 90Sr in the horizontal column 2 without humus is basically same with simulation experiment results in vertical column.