Test specimens were made from ordinary Portland cement (OPC) pastes containing different percentages of Acrylamide. It was measured the strength with time change. The effect of different percentages of Acrylamide on the sulfate resistance and inner pore distribution of lightweight aggregate concrete was investigated.. Test specimens were studied by X-ray diffraction, electron microprobe analysis and mercury porosimetry. The results show: The best percentage of Acrylamide was about 4%, which leads to the higher compression strength. when the content of Acrylamide was 4%, the Sulfate-Corrosion Resistance reached the climax.