The present invention relates to a multi-functional specimen collector, comprising: a barrel on a surface thereof are marked a first graduated section and a second graduated section； a shaft body disposed in the barrel； a piston disposed in the barrel and connected to the shaft body； a first seal cap connected to an end of the barrel； and a second seal cap for connecting to the piston after the shaft body is removed. When a needle is fitted to the barrel, a specimen is extracted into the barrel with the coordination of the needle, the shaft body and the piston； after extraction the needle and the shaft body are removed, and the barrel is sealed up with a first seal cap and a second seal cap respectively for subsequent centrifugal treatment of the specimen； and then the first and second seal caps are removed for expelling any wanted or unwanted specimen materials from the barrel at the push of the shaft body； wherein the double effect of specimen extraction and expulsion is achieved, and wherein an accurate volume of specimen may be extracted or expelled with the help of the first and second graduated sections marked on the barrel.
