A decoding apparatus for a high-density recording medium includes a demodulator, a long-distance code (LDC) processing module, a burst indicator subcode (BIS) processing module, an erasure code generator, and a decoder. The demodulator demodulates data from a high-density recording medium to obtain a demodulated data and a demodulation error flag. The LDC processing module and the BIS processing module deinterleave the demodulated data to respectively obtain an LDC data and a BIS data. The erasure code generator sets an erasure flag corresponding to the LDC data according to the demodulation error flag and the BIS error flag. The decoder decodes the LDC data according to the erasure flag. Further, the decoder decodes the BIS data to obtain the BIS error flag.