The present study has been conducted to quantify the spray angle which is a common parameter for sprinkler spray analysis. Imaging processing technique based on the laser visualization is compared with measurement of spray patterns by momentum signal using the piezo-electric sensor. A DPSS laser with 100 mW power and 532 nm wave length was utilized for the visualization of sprinkler spray and the outer spray angle was measured to 145º for the reference operating condition of sprinkler. A spray patternator using momentum signal of spray droplets was made with the piezoelectric sensor array and the diameter of the individual sensor is 20 mm. The measured spray angle using the spray patternator with piezo-electric sensor is ranged about 140°~150° and shows good agreement with that of the laser visualization technique. This study can contribute to understanding the spray characteristics of sprinkler head and utilizing the fire safety analysis with sprinkler activation.