The columnar grains growth characteristics of components prepared by wire arc additive manufacturing have significant effects on mechanical properties. However， current research on fracture behavior is insufficient. The tensile and fracture behaviors of 304 stainless steel thin-wall component along deposition and scanning directions are investigated， and optical microscope （OM）， scanning electron microscope （SEM） and electron backscatter diffraction （EBSD） are used to characterize cross-section fractures， aiming at unraveling the fracture mechanism. The findings show that columnar grains grow along deposition direction， inducing a lower strength than that along scanning direction. But the obvious necking appears at fracture position， with numerous fine dimples distributed， signifying greater plastic behavior. However， the interlayer with coarser columnar grains also becomes the weak region， even fracture within the layer under tensile stress paralleling columnar boundaries. Conversely， scanning direction exhibits a higher strength with lower plasticity， attributed to dislocations suppressed by boundaries under vertical stresses. Additionally， numerous low angle grain boundaries and strain are detected in the fracture， indicating non-uniform dislocation slip and eventual fracture under strain concentration.