Forward error correction (FEC) may reduce the bit-error ratio (BER) and provide coding gain, so FEC is considered as a mandatory part in 10 Gbit/s Ethernet passive optical networks (10G-EPONs). First, the basic concepts of FEC and Reed-Solomon (RS) code are introduced in this paper. After a detailed description of the implementation of FEC in 10G-EPON, computed result shows that FEC based on RRS(255,223) can meet the need of 10G-EPON’s high power budget. Therefore, FEC is the performance choice with high added value in 10GEPON.