Abstract: Infrared modulation detection technique is used to detect performance of scanning integral type electro-optical radar modulator. An optical transmission and laser collimation system are designed in this paper, which matches inherent properties of the modulator. Based on standard servo control theory, axis scanning model of Ⅲ system with stable condition is established for modulation of pulse code signal. Through FOV's switching of intercepting and tracking, and modulation of driving voltage amplitude, simulated infrared-converged laser scanning beam is coincided with 3°×3°, 40′×40′ cross target. Deviation of scanning FOV and zero position precision are metered, calibration mirror vibration position and scanning frequency zero-crossing pulse are collected in order to achieve infrared signal modulation performance detection. Results show that accuracy of infrared modulation detection technique is better than 0.5′(1σ), accuracy of zero error is less than 5′(1σ), and relative error of the system is less than ± 1%.It meets accuracy requirements of electro-optical radar in infrared optical axis assembly process, and can be applied to linear array scanning integral type modulator performance testing.