A method and system for encoding the low density generator matrix code are disclosed. The encoding method includes the following steps: S102, constructing a generator matrix Gldgc with L rows and N+L−K columns, wherein a phalanx Gldgc(1:L, 1:L) which consists of L rows and the first L columns of the generator matrix Gldgc is an upper triangular matrix or a lower triangular matrix, the K, L and N being positive integers, and K