We have extracted the activity coefficients, f, of benzene, toluene, o-, m-, and p-xylenes, naphthalene, m-dichlorobenzene and p- dichlorobenzene in 25 aqueous salt solutions at 25℃. (The salts used were NaF, KF, LiCl, KCl, LiBr, KBr, NaNO~3, NaClO~3, NH~4Br, NMe~4Br, NH~4Br, (NH~4)~2SO~4, K~2SO~4, MgCl~2, SrCl~2, BaCl~2, MgSO~4, HCOONa, CH~3COONa, C~2H~5COONa, etc.) The relation between logf and c~s (salt concentration, 0-0.8mol.dm^-^3) was identical with Setchenow's formula. We calculated the theoretical values of benzene and it's derivatives in 25 aqueous salf solutions mentioned above. The were 1)Dybye and MacAulay; 2)Conway et al; 3)McDevit and Long; 4) The scaled partical theory; 5)The internal pressure theory modified by Xie et al; 6)Bockris' dispersion energy theory by Li et al. By comparison we can see the calculated values from the modified is simple when using modified dispersion energy theory, and it can be used to determine the signs of salting-out effect (whether they were negtive or positive).

Key words: BENZENE, METHYLBENZENE, DIMETHYLBENZENE, DICHLOROBENZENE, NAPHTHALENE, SODIUM FLUORIDE, LITHIUM CHLORIDE, SODIUM BROMIDE, ACTIVITY COEFFICIENT, SALT EFFECT