Understanding and monitoring the wildlife population and its dynamics is the major task for nature reserves.Infra-red camera is a useful tool for monitoring animals and has been widely used in mammal resource survey,wildlife damage,nest ecology,population estimates,behavioral ecology,etc.To survey and monitor the wildlife resources of Beijing Songshan National Nature Reserve,we set infra-red cameras in 210 sites,with each site maintained for one month,from May to December,2010.The cameras totally took 2203 photos,among which 73% were mammals,12% were birds,13% were staff members,and 2% were other people.We have identified 17 species of mammals(belong to 5 order and 10 family) and 36 species of birds(belong to 5 order and 17 family).The most common mammals occurred on photos included Rock squirrel(Sciurotamias davidianus)、Hog badger(Arctonyx collaris)、Lerpord cat(Prionailurus bengalensis)、the European badger(Meles meles)and raccoon dog(Nyctereutes procyonoides),and the most common birds were the Blue Whistling-thrush(Myophonus caeruleus)、 the Common Pheasant(Phasianus colchicus)、Euroasian Jay(Garrulus glandarius)、the Koklass Pheasant(Pucrasia macrolopha)and the Chinese Thrush(Turdus mupinensis).The photographic rates(PR) varied at different elevation,habitats and seasons: PR was significantly higher in elevation of 1000 — 1400m than that of 600 — 1000m and 1400 — 1700m;PR in broad-leaf forest was the largest,and was similar low in conifer,mixed conifer and broad-leaf forest and shrub;PR in autumn(August to October) was the highest,while in summer(June to July) was low,and in winter(November to December) was the lowest.The cumulative species number taken by infra-red cameras increased with camera days,but the trend slowed down.Infra-red cameras are more suitable to survey and monitor medium-large mammals and some birds and the photos and video of wildlife which are taken by infra-red cameras can be served for the monitoring,research,and environmental education of nature reserves.At the last part of the paper,we discussed the details of techniques on using infra-red cameras to survey and monitor biodiversity.