The methods of gate extraction and injection FET and channel carrier quantity control related to microelectronics technology and semiconductor technology. The gate extraction and injection FET of the invention is provided with a source, a drain, a gate and a channel semiconductor area on the insulating layer. A gate dielectric layer is arranged between the gate and the channel semiconductor region, wherein, the gate dielectric layer is a thin film material with resistance values of 103-1016Ω and the channel semiconductor region is a two-dimensional semiconductor or a three-dimensional semiconductor with two-dimensional semiconductor material characteristics (1-10 cellular crystal layers). The advantages of the invention are that the power consumptions of the devices and the integrated circuits can be greatly reduced by a few orders of magnitude.