A network coding method in a relay apparatus, comprising: obtaining network coding information, wherein the network coding information is generated automatically by the relay apparatus and comprises information of a candidate network coding vector set and a candidate transmission rate set, and transmission rates in the candidate transmission rate set are in one-to-one correspondence with network coding vectors in the candidate network coding vector set; selecting a full rank network matrix according to the network coding information; and coding received source node information according to the full rank network matrix; characterized in that the selecting a full rank network matrix according to the network coding information comprises: sorting all transmission rates in the candidate transmission rate set in descending order, to obtain a test rate set; when the number of the relay apparatuses is n, using the n th transmission rate in the test rate set as a test rate; selecting one network coding vector from each candidate network coding vector set corresponding to the relay apparatus, to form a test coding vector matrix, wherein a transmission rate corresponding to the selected network coding vector is greater than or equal to the test rate; and if the test coding vector matrix is a full rank matrix, determining that the test coding vector matrix is a full rank network matrix; or, the selecting a full rank network matrix according to the network coding information comprises: a. sorting all transmission rates in the candidate transmission rate set in descending order, to obtain a test rate set; b. when the number of the relay apparatuses is n, using the n th transmission rate in the test rate set as a test rate; c. selecting one network coding vector from each candidate network coding vector set corresponding to the relay apparatus, wherein a transmission rate corresponding to the selected network coding vector is greater than or equal to the test rate; and d. if a test coding vector matrix cannot be formed according to the selected network coding vector, or a test coding vector matrix formed according to the selected network coding vector is not a full rank matrix, sequentially using a transmission rate next to the current test rate in the test rate set as a new test rate, and repeating step c until it is determined that the test coding vector matrix is a full rank matrix.. obtaining network coding information, wherein the network coding information is generated automatically by the relay apparatus and comprises information of a candidate network coding vector set and a candidate transmission rate set, and transmission rates in the candidate transmission rate set are in one-to-one correspondence with network coding vectors in the candidate network coding vector set; selecting a full rank network matrix according to the network coding information; and coding received source node information according to the full rank network matrix; characterized in that the selecting a full rank network matrix according to the network coding information comprises: sorting all transmission rates in the candidate transmission rate set in descending order, to obtain a test rate set; when the number of the relay apparatuses is n, using the n th transmission rate in the test rate set as a test rate; selecting one network coding vector from each candidate network coding vector set corresponding to the relay apparatus, to form a test coding vector matrix, wherein a transmission rate corresponding to the selected network coding vector is greater than or equal to the test rate; and if the test coding vector matrix is a full rank matrix, determining that the test coding vector matrix is a full rank network matrix; or, the selecting a full rank network matrix according to the network coding information comprises: a. sorting all transmission rates in the candidate transmission rate set in descending order, to obtain a test rate set; b. when the number of the relay apparatuses is n, using the n th transmission rate in the test rate set as a test rate; c. selecting one network coding vector from each candidate network coding vector set corresponding to the relay apparatus, wherein a transmission rate corresponding to the selected network coding vector is greater than or equal to the test rate; and d. if a test coding vector matrix cannot be formed according to the selected network coding vector, or a test coding vector matrix formed according to the selected network coding vector is not a full rank matrix, sequentially using a transmission rate next to the current test rate in the test rate set as a new test rate, and repeating step c until it is determined that the test coding vector matrix is a full rank matrix..