The experiments on the fouling characteristics of sintered porous surface tubing（SPST）in pool boiling were carried out，with CaSO4 solution as a working fluidThe experimental results showed that SPST possessed better antifouling ability compared with smooth surface tube（SST）.The asymptotic fouling thermal resistance increased with increasing concentration of solutionHowever，transition of fouling curve from asymptotic line to straight line was observed when concentration reached a specific levelAn analysis of tubing surface and fouling surface of SPST and SST was made by scanning electronic microscopy（SEM）to interpret the antifouling mechanism of SPSTIt was observed that the crystal grain of CaSO4on SPST surface was hexaprismshaped and 1/2.5 size of that from SST surface with a thinner fouling layer.