Vat　photopolymerization　3D　printing　of　Si3N4　ceramics　has　attracted　great　attention　recently.　To　overcome　the　low　curing　depth　limitation　caused　by　alpha-Si3N4,　beta-Si3N4　with　low　absorbance　and　large　particle　size　was　selected　in　this　paper.　After　printing,　the　effects　of　pressureless　sintering　temperatures　on　mechanical　and　dielectric　properties　were　systematically　investigated.　At　1800　degrees　C,　the　real　permittivity　of　Si3N4　ceramics　was　7.37,　and　the　maximum　bending　strength　was　367　+/-　75　MPa.　Considering　the　application　of　Si3N4　ceramics　in　radomes/　windows,　the　dielectric　constant　of　Si3N4　ceramics　should　be　further　reduced.　Therefore,　the　octet-truss　lattice　structure　was　introduced　to　optimize　the　porosity　of　ceramics.　As　the　porosity　increased　from　25%　to　36%,　the　real　permittivity　decreased　from　5.56　to　4.42,　and　the　bending　strength　ranged　from　98　+/-　7-62　+/-　13　MPa.　It　shows　that　vat　photopolymerization　3D　printing　can　be　a　promising　technology　for　the　fabrication　of　wavetransparent　Si3N4　ceramics.