Extract of plant Dendrobii caulis and preparing process thereof

A process for preparing an extract from a plant of Dendrobii Caulis, comprising steps of:

• a) obtaining a first alcohol extract from said plant;
• b) extracting said first alcohol extract by water and an alkane simultaneously for obtaining a first water layer and an alkane extract;
• c) extracting said first water layer by an ester for obtaining an ester extract and a second water layer;
• and
• d) extracting said second water layer by a second alcohol for obtaining a second alcohol extract and a third water layer.