<p>The ultrasonic rolling strengthening technique (URST) is a vital method for enhancing surface properties and extending the service life. The exploration strives to investigate micro-process of URST applied to quenched 42CrMo steel. Through ultrasonic rolling strengthening experiments and advanced microstructural analysis methods such as EBSD, the study systematically reveals role about URST associated mechanical behaviors. The results indicate that URST significantly refines surface grains, transforming grain boundaries with a steep misorientation into boundaries with slight misorientation, plus the proportion in low-angle grain increasing from 44.8 to 65.7%. Surface texture also evolves during the process, shifting from a dominant &lt; 101 &gt; orientation to &lt; 111 &gt; and &lt; 001 &gt; orientations, with &lt; 001&gt;-oriented grains becoming more prevalent. The dislocation density dramatically increases, with the maximum dislocation density rising from 18.97 × 10¹⁴/m² to 43.03 × 10¹⁴/m². Additionally, URST induces the formation of α-fiber and Goss textures while promoting dynamic recrystallization. The interplay between dynamic recrystallization and dislocation accumulation is identified as a key factor driving grain evolution and surface performance enhancement. The findings contribute in-depth micro-process of URST plus offer valuable guidance for refining the surface attributes of 42CrMo steel plus other materials.</p> Graphical Abstract <p></p>