Cracking morphology in the fusion zone of HQ130 high strength steel was researched by the y-slit test and three-point bend test, ultrasonic test and microscope. HQ130 and Q J63 high strength steel was welded by Ar+CO2 gasshielded arc welding under the condition without preheating. Experimental results indicated that welding cracks wereproduced in the partially melted zone of the weld root of HQ130 steel side and propagated parallel to the fusionzone. The cracks were developed altatively between the weld and the partially melted zone, and are not strictlyruptured at W/F (weld metal/fusion zone) boundary surface. Controlling weld heat input (E) about 16 k J/cm couldmake the cracking rate lowest and satisfy the performance requirement of welded joint zone.