Purpose　-　The　paper　aims　to　summarize　the　design　theory　for　labyrinth　channels　of　water　saving　emitters.　Design/methodology/approach　-　On　the　basis　of　extracting　the　structural　parameters　of　labyrinth　channels　in　water　saving　emitters,　the　hydraulic　performance　experiments　on　the　integral　emitters　fabricated　with　higher　resolution　rapid　prototyping　technology　are　performed.　Then,　using　multivariable　linear　regression,　formulas　of　pressure　versus　flow　rate　and　regression　plots　for　different　emitters　are　induced.　Findings　-　The　formulas　of　flow　rate　versus　structural　parameters　are　summarized　based　on　the　trapezoid-type　channel　unit,　and　verified　through　experiments.　The　relationships　between　flow　rate,　pressure　and　structural　parameters　of　channels　are　established.　Research　limitations/implications　-　The　effect　of　emitter　fabrication　error　on　the　flow　rate　is　analyzed,　which　provides　a　basis　for　parameterized　structural　design　and　accuracy　control　in　the　fabrication　of　future　emitters.　Practical　implications　-　The　Q-H-n　relationship　equations　are　used　to　design　emitters　which　have　flow-rate　errors　under　both　high-　and　low-water　pressure　of　less　than　4　percent.　So　the　Q-H-n　relationship　equation　of　the　emitter　is　well　proven　and　accurate　which　can　guide　the　design　for　the　structure　of　emitters　with　trapezoid　labyrinth　channels.　Originality/value　-　In　this　paper,　a　new　stereolithography　system　has　been　used　to　fabricate　accurately　a　drip　irrigation　emitter　with　a　complex　microstructure,　which　cannot　be　obtained　with　conventional　RP　or　other　manufacturing　processes.　Compared　to　other　manufacturing　process,　this　new　technique　has　higher　manufacturing　accuracy　and　can　reduce　the　manufacturing　cost　and　time.　Furthermore,　a　design　theory　for　labyrinth　channels　of　water　saving　emitters　is　established.