This publication continues coverage study on plasma parameters distribution in the discharge channel of the stationary plasma thruster and is devoted to the description of probe characteristics measuring. Problems of probe measurements in the discharge channel are shown and the ways of their solving is presented. Designs of used single and emissive probes are presented, as well as electrical circuits. Voltage-current characteristics of a single probe, as well as the characteristics of the emissive probe, measured inside the channel of M70 type SPT are presented. The influence of a probe introduction into the channel on the discharge current of the thruster is shown. The estimation of accuracy of the measurement probe characteristics is given.