To study the bending tensile performance of alkali-activated slag ceramsite concrete hollow block (AASCHB) masonry, tests on 108 masonry specimens with Mb25~Mb90 of alkali-activated slag mortar with pottery sand (AASM) were carried out. The experimental results show that the formula calculation based on Table B.0.1-2 of GB 50003—2011 cannot exactly estimate the bending tensile strength of AASCHB masonry with AASM. When the compressive strength of mortar was lower than 70.3 MPa, the formula calculation of the bending tensile strength along straight joint was higher than the test result.When the compressive strength of mortar was between 70.3 MPa and 91.9 MPa, the formula calculation of the bending tensile strength along straight joint was lower than the test result. The formula calculation of the bending tensile strength along slot joint was higher than the test result as the compressive strength of mortar was lower than 46.2 MPa.When the compressive strength was in the range of 46.2 MPa to 91.9 MPa, the formula calculation of the bending tensile strength along slot joint was lower than the test result. It was found that the bending tensile strength of AASCHB masonry was not only related to the compressive strength of AASM, but also affected by the factors of water to cementitious material ratio, sand to cementitious material ratio, Na₂O content, and silicate modulus.Based on the experimental results, the formulae for the bending tensile strengths of AASCHB masonry along straight joint and slot joint were developed, respectively.