Abstract: In order to obtain the optimal cutting quality of fracture splitting groove on connecting rod made of new material 36MnVS4, experimental study and theoretical analysis of crack groove fabricated by laser cutting were investigated through orthogonal experimental method. Geometric dimensions such as depth, width, opening angle and curvature radius of fracture splitting groove produced by laser cutting were measured and calculated by laser confocal microscope, respectively. In addition, microstructure and thickness of heat affected zone on the bottom of crack groove were observed and measured by adopting scanning electron microscope. The effects of laser peak power, pulse width, cutting speed and pulse frequency on geometric dimensions of fracture splitting groove were analyzed by using range analysis method. As a result, the optimal parameter combination of cutting fracture splitting groove were found out. The results show that, the depth of heat affected zone on the bottom of crack groove is less than 100μm and there exist micro cracks and pores. The investigated parameters have less impact on the width, opening angle and curvature radius of fracture splitting groove, but have large effect on depth. Moreover, laser peak power and pulse width exert great influence on depth of crack groove, while cutting speed and pulse frequency have little effect on it. The optimal parameters exist with cutting speed of 1.0m/min, laser peak power of 700W, pulse frequency of 1000Hz and pulse width of 50μs. The study is of great importance for actual production.