The simulating tests by using soil and solution cultivation showed that annual woody-plants have certain tolerance to mercury and the tolerant capacity varies with different tree species. The order is as follows.populus canadensts>populus xeura-mericana>salix matsudaria>populus nummowiczii.In the P.canadensis, the tolerant threshold cocentration to mercury is about 95-100ppm and the maximum absorbed amount of mercury is about 6779Hg. Above the threshold, the growth and development of the plants appear evide...