MTNP OAM message sending method and device

The invention discloses an MTNP OAM message sending method, which comprises the following steps of: depicting a complex OAM indication MOI, counting effective service data of each channel, and adding 1 to the MOI value every time n * 16k 66bits code blocks are passed; detecting a free block pattern and an Ethernet packet header in the data stream, and obtaining a current first free block mark and a first packet header mark; and generating insertion requests of a basic message BAS, an automatic protection switching message APS and a low priority message LOW according to the described MOI, the free block mark and the packet header mark. Error code counting caching instead of pure error code caching is adopted, and compared with the mode that FIFO is adopted to cache error codes, occupied resources are small, power consumption is small, and control is easy. The circuit is wide in application range and can be applied to any circuit with reverse insertion error codes. The circuit is also easy to expand and is suit