Abstract：In 2-D seismic exploration，in order to avoidinterrupt phenomenon on seismic reflection sec-dons because of the obsta#les on surface，the de-sign of geometry-changed pattern should be neededso that the obstacles (rivers and towns etc.)couldbe crossed and continue tracing and correlation ofreflection events could be guaranteed.In formerfield production,irrational design of obstacle-cross-ing geometry sometimes not only increasesprospecting cost，but also affects the acquisitionquality.Therefore，only scientific and reasonabledesign of obstacle-crossing geometry and parame-ters can ensure the seismic lines successfully pass-ing through the obstacles,obtaining better seismicdata under the obstacles and reducing the prospect-ing cost.For that reason,on the basis of investigat-ing and studying a lot of practical obstacle-crossinggeometry,the paper summarized three types of ob-stacle-crossing geometry and analyzed the proper-ties and applied scope.Using schematic method,theparameters formulas of crossed width，minimumoffset and maximum offset in key patterns havebeen deduced.Using the set of obstacle-crossinggeometry patterns can not only obtain the seismicdata with good quality equal to that on the bothsides of obstacles，but also effectively reduce theprospecting cost.
