Abstract: The present invention herein relates to a sample injection device for micro gas chromatograph is assembled from five layers of thin plates and membrane. The first layer serves as cover plate and interfacial connection to outside columns. The second layer is fabricated with a sample channel and a carrier gas inlet split into an analytical channel and a reference gas channel, and two valve seats. The third layer is a flexible diaphragm for valve actuation. The fourth layer is fabricated with a pressurizing gas inlet hole and pressurizing channel leading to the diaphragms of valve seats. The fifth layer serves as another cover plate. An external solenoid valve is used to control the processes of sampling and injection. The channels and valve seats on each layer plate can be fabricated through several well-developed fabrication techniques such as photolithographic, LIGA processes or precision micro machining. All five layers are properly aligned and bonded by adhesives.