The invention discloses a method and a system which can send stream media data with zero copy, which is based on the network protocol stack of Linux. The method of the invention comprises the steps as follows: when a stream media server receives the data request of user equipment, the system calling of data to be transmitted is carried out; the stream media data is read into a user data cache from the hard disk space; the stream media data memorized in the user data cache is packaged as real-time transmission protocol data packages; the transmission of stream media data package with separation of head and load is adopted for the real-time transmission protocol data. The method and the system of the invention sufficiently use the DMA function and SG (Scatter/Gather) function of a network card and realizes a type of stream media data transmission with zero-copy; compared with the existing network protocol stack of Linux kernel, the method and the system of the invention realize the transmission type of stream media data packages with separated head and load, and reduces the once data copy operation required during the RTP packaging process of the stream media data.