1. Look at the price of LED chips in general, the price of led chips is higher than the price of wafer, high-power led chips must be higher than low-power led chips, imports are higher than domestic, and the source price of imports is reduced from Japan, the United States and Taiwan. 2. Look at the quality evaluation of led chip The quality of led chip is mainly measured from the two main standards of bare crystal brightness and attenuation, and is mainly calculated from the yield of led chip package in the packaging process. 3. The surface flatness of the LED display should be within 0≤a≤1mm to ensure that the display image does not distort, and the local bulge or concave will cause the viewing Angle of the display to appear dead. The quality of flatness mainly depends on the production process and materials; ② On-site steel engineering construction; ③ Display installation team installation construction quality decision. 4. Brightness and viewing Angle The brightness of the indoor full-color LED display should be above 800cd\/m, and the brightness of the outdoor full-color LED display should be above 1500 cd\/m, in order to ensure the normal display of the LED display, otherwise it will be too low and can not see the displayed image. The brightness is mainly determined by the quality of the LED tube core. The size of the viewing Angle directly determines the amount of space for the viewing area of the LED display, so the larger the better. The size of the viewing Angle is mainly determined by the LED chip. 5. White balance effect White balance effect is one of the most important indicators of LED display. Color science when the ratio of the three primary colors of red, green and blue is 1:4.6:0.16 will show pure white, if the actual proportion is a little deviation there will be a deviation of white balance, generally pay attention to whether the white is blue, yellowish green phenomenon. The quality of white balance is mainly determined by the LED chip, and the LED chip also has an impact on the reducibility of color. The reducibility of color refers to the reducibility of the LED display to the color, both the color of the LED display to maintain a high degree of consistency with the color of the playback source, so as to ensure the reality of the image. 7. There is no Mosaic, dead point phenomenon Mosaic refers to the LED display on the steady or often black small four squares, both module necrosis phenomenon, the main reasons are: ①LED display used by the connector quality is not high or concave phenomenon; ②LED lights are not corrected; ③ The sealing adhesive process is not qualified.