Fracture path deviation (FPD) is often observed in the standard Charpy V-notch (STD-Cv) test on laser welded joints due to the sharp gradient of hardness distribution. The side notched Charpy V-notch (SN-Cv) test is studied to avoid FPD. Fundamental study on the comparison between STD- and SN-Cv test on laser welded joints for high strength ultra-fine grained steels and on base metal for conventional high strength steels indicates that the results obtained from SN-Cv test gives higher transition temperature and lower absorbed energy than those of STD-Cv test. The fracture surface of Cv test is composed of three types of ductile fracture (fibrous fracture at notch tip, slant fracture at both sides and ductile fracture at the edge) as well as brittle fracture. The unit fracture energies for the fracture surfaces are determined by using regression analysis method. Finally, relationship between STD-Cv and SN-Cv is discussed.