A　practical　revolution　in　construction　could　be　realized　by　combining　the　potential　of　3D　concrete　printing　with　lightweight　cementitious　materials　to　fabricate　adeptly　hollow　structures.　In　this　study,　five　concrete　mixtures　with　different　replacement　rates　of　lightweight　ceramsite　sand　to　silica　sand　are　prepared　for　extrusion-based　3D　printability　evaluation.　To　reduce　the　water　absorption　induced　shrinkage　and　micro-cracks,　the　ceramsite　sands　were　coated　with　polyvinyl　alcohol.　An　optimized　cementitious　material　was　identified　by　harmonizing　the　fresh　properties　to　the　continuous　printing　process.　Cubic　and　beam　elements　with　four　different　types　of　interior　hollow　structures　were　designed　and　3D　printed　based　on　the　optimized　lightweight　mixture.　The　interior　structures　include　cellular-shaped　structure,　truss-like　structure,　lattice-shaped　structure　with　a　square　topology,　as　well　as　gridding　shaped　structure　with　triangle　topology.　The　mechanical　capacities　of　the　printed　samples　were　measured　and　evaluated　by　compressive　tests　for　the　cubic　samples　and　four-points　flexural　bending　tests　for　the　beam　specimens.　Basing　on　the　results,　the　rectangular　lattice　hollow　structure　demonstrates　the　best　mechanical　resistance　to　compression　and　the　truss-shaped　prism　structure　ensues　the　highest　flexural　properties.　The　stress　distribution　and　failure　process　were　also　explored　through　discrete　element　method.