Abstract: There are strong electromagnetic interferences on instantaneous electron beam parameters measurement system in LIA. The transient pulses, which may affect both circuits and measurement system, are harmful to electronic devices and capturing effective data. The principle of instantaneous electron beam parameters measurement system is introduced in this paper, while the formation mechanism and the suppression method of transient pulse interferences are analyzed. Arrangement of the system is also proposed. The effects on electron devices performance by transient pulse interference and the preventive method are discussed, too. By using optical fiber, which effectively reduced the delay jitter of narrow pulses, the reliability requirement of high-speed control signal propagation was fulfilled. To provide better protection for the electronic devices of beam parameter measurements, the anti-electromagnetic interference ability of the system was enhanced by compactly-embedded method. The reliability of the overall measurement system was significantly improved as a result.