Aiming at directional blasting demolition engineering of chimney with blasting cut height at about 100 meters in the complex environment, in order to study the influence of the combination incision of Triangle Rectangular and Inverted Triangle Rectangle for the collapse and stress process of chimney,two kinds of reinforced concrete chimney separate common node models were established and studied systematically using LS-DYNA software. The results shows that the neutral axis stabilization time of about 2~3s (incision coefficient K=0.56~0.58) is the key to prevent appearing too early sit down and forming a directional dumping trend of the chimney after the formation of blasting incision; The compressive stress of the concrete inside the support body is greater than that of the outer concrete, the Inverted Triangle Rectangle combination incision can delay the pressure shear failure and the speed of neutral axis backward than the triangle rectangular combination incisionwhich is conducive to achieve safe and exact orientation of the chimney; As the inverted triangle rectangle combination incision has some common features with inverted trapezoidal and inverted triangle trapezoid combination incision, the incision shape is recommended to use the inverted triangle incision in the directional blasting of high location incision of chimney.