Cylinder with multiple diagonal slits is one of the core parts of longitudinal-torsional resonance ultrasonic device. Its structure was more complex, the traditional processing processed it very difficult, and the traditional analytical methods were also difficult to make accurate description to system. The paper researched cylinder with multiple diagonal slits using experimental method, analysis of electrical discharge machining forming tools of the slits and three-dimensional modeling; developed cylinder with multiple diagonal slits, analyzed longitudinal-torsional resonance and mechanical properties of cylinder with multiple diagonal slits using finite element analysis method. Tested resonant frequency of cylinder with multiple diagonal slits with precision impedance analyzer. The finite element analysis results compared with tested results, and analysis of error between them, finite element analysis results slightly lower than the test results but the error was within the allowed range. Comparison of results and analysis of error indicated that developed cylinder with multiple diagonal slits meet requirement.