The invention discloses a flow passage structure design method for an anti-clogging drip irrigation emitter. The method is based on computational fluid dynamics CFD and particle image velocimetry PIV, corrects flow passage structure parameters by means of combining CFD simulation, LRP test sample fast manufacturing and PIV visualized test, processes samples, performs a muddy water anti-clogging test according to relevant international standards, and finally realizes product structure setting and mode opening production. The method can remarkably improve anti-clogging property of the emitter. The method is adopted to perform quadratic optimization of a ladder-type flow passage structure of the drip irrigation emitter and standardize optimizing parameters, thereby normal irrigation days of the emitter are added to 11 days from 6 days before the optimization; maximum sand content is decreased to about 5 % from over 60 %; and anti-clogging property of the emitter is remarkably improved.