The system of RF control of three-electrode electron gun current is described. It consists of a source of microwave signal, coaxial line, coaxial RF switch and RF antenna lead. The system allows one to get the electron beam in the form of bunches with the frequency of the accelerating section to achieve the capture of particles in the acceleration mode close to 100%. The results of calculation and analysis of the elements of the system are presented. Characteristics of the devices are obtained experimentally. The results of using RF control in three-electrode electron gun at electron linear accelerator are described. KEYWORDS: Hardware and accelerator control systems; Accelerator Subsystems and Technologies; Instrumentation for particle accelerators and storage rings -low energy (linear accelerators, cyclotrons, electrostatic accelerators); Ion sources (positive ions, negative ions, electron cyclotron resonance (ECR), electron beam (EBIS))