The Asian-Pacific Oscillation (APO) is a zonal teleconnection pattern of the eddy temperature field in the middle and high troposphere over the extra-tropical Asian-Pacific region. Its anomalous change is closely related to the Asian and Pacific summer monsoon. Based on the monthly European Center for Medium-Range Weather Forecast reanalysis data ERA-40 and numerical simulation of the BCC_CSM1.1 (m) model in Beijing Climate Center, this paper evaluates the ability of BCC_CSM1.1 (m) model in simulating the summer APO spatial distribution, evolution of APO index and the climate differences between the higher and lower APO index years. Results show that BCC_CSM1. l(m) can well simulate the out-of-phase relationship in the upper-tropospheric eddy temperature between Asia and North Pacific mid-latitudes in Northern Hemisphere summer,and the model is also able to successfully simulate the interannual variability of APO index,but fails to catch the significantly decreasing trend in 1960s1970s. Furthermore,BCC_CSM1. l(m) can successfully reproduce the Asian and Pacific summer monsoon climate changes corresponding to the APO index variation. With higher APO index conditions,the summer South Asian high and the North Pacific trough are stronger,while the westerly jet stream over Asia and the easterly jet stream over South Asia both strengthen in the upper troposphere. Meanwhile,the Asian low and the North Pacific subtropical high are stronger in the lower troposphere. The anomalous southerlies prevail at 40°E50°E longitudes and the mid-latitudes of East Asia,and the anomalous westerlies prevail over South Asia. Summer rainfall increases in South Asia and northern of East Asia,while it decreases from the Yangtze River Basin to Japan and the Philippines region,and vice versa.