For the closed distance communication among urban buildings,the influence of inherent position error between the receiving aperture and the transmitting aperture is analyzed.The new model of link energy with inherent position error is established.The link energy data are calculated under different inherent position error,and the relationship between the link energy and the inherent position error is analyzed.Taking the inherent position error of 15mm as an example,the link energy under different distances is calculated.On the basis,the actual communication verification test is conducted,the specific test operation process is given and the measured data with the distance of 10m,40m and 1000m are obtained.Comparing with the theory data,the experimental data shows that the maximum error is less than 0.52dB.The correctness of the theoretical energy model is verified.The energy model can be used to guide the design of remote distance communication terminal.At the same time,the successfully development and communication test can effectively accelerate the application of civil communication for urban buildings.