As the name suggests, a single touch is one point at a time, and if two or more points fail or one of them works.Multi-touch can touch several points at the same time, all of which are valid.
Single touch control in many hospitals, libraries and other halls have this touch technology computer, mobile phones, MP3, digital cameras supporting touch screen also use this technology.This kind of screen brings two advantages to the user interface. First, the design space of the device is optimized, especially for small devices, because they can 'install' the screen and buttons in the same area at the same time.Second, because the button can be integrated in any application of the operating system, so the device can use the 'button' can be unlimited.Multitouch is often used to play mobile games.Apple's iPhone, for example, USES multi-touch.
Single-touch is usually resistive screen, multi-touch is mostly capacitive screen.
Compared with multi-touch, single-touch can recognize and respond to more than one point (two points, three points or even more points) at the same time.So now some of the electronics industry is turning to multi-touch technology.