Thermoluminescence (TL) and optical stimulated luminescence (OSL) dose response curves of alkaline-earth sulfate doped with rare earth ions were measured. The non-linear dose response parameters were obtained by using the composite action dose response model. It is concluded that the linearity of dose response is relative to the species of rare earth ions and the defect structure. The one-hit factors (R) are closes to 1 in sulfate phosphors doped with Eu ions

which means that the dose responses are sublinear. But the dose responses are supralinear since R < 0.5 when sulfate phosphors were doped with Tm or Dy ions. The value of R decreases with the increasing of TL peak temperatures

which means that contribution to dose response from the two-hit events is increased. The experiments also show that the dose response parameters of OSL are similar to those of TL.