Abstract: In the field of smoke screen technology, the total obscure power (TOP) is a characterization parameter of smokescreen obscure power for human visual. A smokescreen TOP testing system, which can implement the automatic TOP measurement, was developed based on the irradiance measurement technology. This system is stable, efficient, real-time and reconfigurable. Under the conditions of 26℃ and 80% relative humidity, a test for yellow phosphorus-derived smoke TOP was performed. It was verified that the test result conformed with the empirical value.