We have developed a metal vapor vacuum arc ion source, which was used for film deposition. Based on this source, some experimental diagnostics of plasma parameters are presented in this paper. Characters of vacuum arc cathode spots, including number, size, motion, and lifetime, are studied using a high‐speed photograph technique. Substrate bias voltage dependence of plasma microparameters, such as electron density and electron energy, are measured by a Langmuir probe measurement system. In conclusion, some discussion of experimental results are also presented.