The production of acrylates from biomass-originated lactic acid is of extraordinary importance to overcome the increasing worldwide shortage of petroleum. In this work, the catalytic dehydration of lactic acid to acrylic acid was carried out over calcium sulfate catalyst with cupric sulfate and phosphates as promoters. The mass ratio of m(CaSO4)/m(CuSO4)/m(Na2HPO4)/m(KH2PO4) is 150.0:13.8:2.5:1.2. In the dehydration of lactic acid, effects of carrier gas, calcination temperature for catalyst, concentration of lactic acid as well as contact time are discussed in detail. With carbon dioxide as carrier gas, the highest acrylic acid yield of 63.7% is achieved from 26 wt.% lactic acid at 330 degrees C and 88 s contact time.