One of the week points for LDPC encoding is the computational complexty in communication system.An efficient encoding was presented by Richardson who approached making codeword by using parity check matrices with low density.In this paper,we focus on computational complexty of richardson's LDPC matrix which is composed by matrix A,B,C,D,E and T .We propose two schemes for low complexty encoding.First one accomplishes T-1 =E=I and resticts D consiting of dual diagonal matrices and second one achieves T-1=0-1=I. Therefore the constraint reduces complexty from O(n+g�) to O(n) and efficiently omits some process of econdin.Also,we perform numerical experiments on our matrices.Proposed schemes can be useful for high-rate and high-speed communication systems due to reduced complexty and retrenched processes of econding.