In the present,smartphone have a role in our daily life more especialy in youth are using it increasing. Smartphone became another factor that the most important Thai youth Because of the advantages it is convenient to find the information,fast communication and entertainment. In addition to watch movies, listen to music, it is also an area of themselves as talent show, singing, dancing through the Internet. Another is the disadvantage is the relationship with the people around you down, Problems with eye trouble And grade lower because of using it too much. However, using a smartphone, it has both advantages and disadvantages , depending on the split time, which should be used, or how we should not. If teenagers are known to use the smartphone correctly, it will benefit us greatly. But on the other hand, It will take effect as if the Split time was not right.