316L stainless steel HVAC pipe was used as the base material. Laser surface treatment and powder embedding and aluminizing were used to enhance the surface treatment of 316L. The influence of power density on laser impingement aluminizing structure and thermal tensile properties of the 316L surface were studied through experimental testing methods. The results show that there are more pits in the aluminized layer after laser shock. With the increase of power density, the roughness increases. With the increasing of power density, the diffraction peak becomes stronger. As the depth increased, the hardness continued to decrease. With the increasing of laser power density, the hardness increases. The mechanical properties of samples treated by laser shock intensification are better. With the increasing of laser power density, the mechanical properties are improved more obviously. Higher mechanical properties were obtained when the power density was 6 GW/cm2, and the tensile strength and yield strength are 531 MPa and 443 MPa, respectively. After laser impact, many equiaxial dimples with different sizes were observed at the fracture site, and tear edges were generated, generating a large number of dimples. After increasing the laser power density, the size difference of each dimple becomes more obvious, and the hole size also increases.