Laser has been widely applied for advanced material processing,such as welding of advanced high strength steels(AHSS) for automotive applications and Pt,Ti,and Nitinol alloys for medical applications.Recently,ultrafast pulse laser,especially femtosecond laser,is identified as powerful tools for joining and surface engineering of nanomaterials.This paper reviews our research on these fields at the Centre of Advanced Materials Joining,University of Waterloo.Representative conclusions are listed for laser material processing at three continuing scales.1) For AHSS welding,a thin Al layer can dramatically enhanced the weldability of galvannealed AHSS.The movement of the welding line and softening in the vicinity has significantly influence on global mechanical properties in dual phase(DP) and transformation induced plasticity(TRIP) steels.The increase of the strength ratio decreases the formability and results in the non-uniform strain distribution.2) For medical micro-welding,oxygen is found to be a key role for welding strength and microstructure.The formation of intermetallics reduces the relative ductility and increases the susceptibility of cracking.Different laser processing parameters can significantly influence weld mechanical performance.3) For femtosecond laser nanofabrication,the joining of Au nanoparticles is successfully achieved by controlling laser energy.Surface nanostructure of Ag induced by femtosecond laser irradiation can work effective probes for surface enhanced Raman spectroscopy. Laser has been widely applied for advanced material processing, such as welding of advanced high strength steels (AHSS) for automotive applications and Pt, Ti, and Nitinol alloys for medical applications. Reactively, ultrafast pulse laser, especially femtosecond laser, is identified as powerful tools for joining and surface engineering of nanomaterials. This paper reviews our research on these fields at the Center of Advanced Materials Joining, University of Waterloo. Representative coordinates are listed for laser material processing at three continuational scales.1) For AHSS welding, a thin Al layer can dramatically enhance the weldability of galvannealed AHSS. The movement of the welding line and softening in the vicinity has significant influence on global mechanical properties in dual phase (DP) and transformation induced plasticity (TRIP) steels. Increase in the strength ratio decreases the formability and results in the non-uniform strain distribution.2) For medical micro-welding, oxygen is fou nd to be a key role for welding strength and microstructure. formation of intermetallics reduces the relative ductility and increases the susceptibility of cracking. Different laser processing parameters can significantly affect weld mechanical performance. 3) For femtosecond laser nanofabrication, the joining of Au nanoparticles is successfully achieved by controlling laser energy. Surface nanostructure of Ag induced by femtosecond laser irradiation can work effective probes for surface enhanced Raman spectroscopy.