Population size of the Black Grouse Lyrurus tetrix was surveyed in Saihanba area in October of 2009. The results showed that its population density was 2. 20 ind. /km². Compared with the former data,its population density showed a downward trend and its distribution pattern in this area changed. The major threats to this declining population are reduction of breeding individuals,low breeding success rate and hunting pressure in fall. At present,the most effective measure to save this population is to stop the hunting with strict management.