In order to meet the requirements of optical communication systems for high code rate and low bit error rate of errorcorrection codes

we present a novel construction method for QC-LDPC codes on the basis of the nature of the field characteristics of Galois field

which is simple in structure

easy to be encoded and can effectively avoid the girth 4effectively

and use this method to construct an FC-QC-LDPC（3969

3729）code that is suitable for optical communication systems.The simulation results show that when the BER=10-7

the Net Coding Gain（NCG）of the constructed FC-QC-LDPC（3969

3729）code with the code rate of 0.937 is about 0.15 dB higher than that of the QC-LDPC（4288

4020）code

and about 0.35 dB and 2.1dB higher than those of the Linshu-QC-LDPC（3780

3542）code and the classical RS（255

239）code respectively.In addition

its performance is about the same as that of Mackay code but has stronger error-correcting performance.So it is more suitable for high-rate long-haul optical communication systems.