Abstract: A method for determination of trace Gd, Sin, Dy, Eu in MnSO_4 is described. The manganese is separated from rare earth elements by cation exchange resin with 2 mol/l HCl as eluent. The concentration of rare earths is determined by ICP-AES. With a sample of 50mg, the determination limit of Gd, Sm is 0.4×10~(-6), Dy, Eu is 0.08×10~(-6), the recovery is in the range of 88%～105%, the relative standard deviation (RSD) is less than 11%.