Abstract: Role of each resistance in ultrasonic inspection transmitting circuit was analyzed in detailedly. A-type-pulse-reflection ultrasonic transmitting circuit was simulated with circuit emulation software firstly. Aiming at solving the peak voltage of activation pulse being a little less than intending peak voltage, algebraic relation between resistance and instantaneous voltage of activation pulse was made correctly based on Kirchhoffs Voltage Law, giving an explanation of the result of emulation above. Furthermore, interrelations between Resistances of transmitting circuit and activation pulse and transmitting pulse are respectively analyzed in detail through the use of emulation experimentation and in theory. Two conclusions about resistance were made at last. One conclusion was that the resistance of switch should not be ignored and the other was that charging resistor and damping resistance should be admeasured suitably.