Telecom has completed the reorganization and the issuance of 3G hcenses

now telecom is completely going into era of full-service competition

we should promote network with saving

efficient

and environmentally-friendly operation.However

after reorganization

the three major telecom operators have a total of six networks

there are lots of waste of re-construction and natural resources growing problems.To explor the technique in the co-construction and sharing work

this paper research the interference isolation needed in coconstruction of basestation between CDMA800 system and multi-systems.According to a widely used type of antennas

we research the actual isolation distance and implementation of the project feasibility for reference.