A transmission electron microscope (TEM) micro-grid includes a base and a plurality of electron transmission portions. The base includes a plurality of first carbon nanotubes and the first carbon nanotubes have a first density. Each electron transmission portions includes a hole defined in the base and a plurality of second carbon nanotubes located in the hole. The second carbon nanotubes have a second density. The second density is less than the first density. The base and the electron transmission portions form the TEM micro-grid for observation of a sample using a TEM microscope.