Effect of five types of cellulose ethers with different substitution degrees and groups at 0.3% and 0.6% dosage on the tensile bond strength of calcium sulphoaluminate（CSA） cement mortar at fixed water to cement ratio was studied. Based on the water retention rate and porosity measured by mercury intrusion porosimeter， the influence and the mechanism of cellulose ether structure on the tensile bond strength of CSA cement mortar were discussed. The results show that for the same cellulose ether， higher substitution degree makes more air entrainment which in turn leads to larger porosity and lower tensile bond strength. For different cellulose ethers， hydroxyethyl methyl cellulose has smaller porosity and higher tensile bond strength than hydroxypropyl methyl cellulose. A model to interpretate the influencing factors on the tensile bond strength of CSA cement mortar is proposed based on the experimental results.