A blutetooth（BT） sensor networks for monitoring square environment is introduced.This network system is able to collect and process environmental information through the means of BT sensor nodes arranged within the reach of a square

which also collect each BT sensor node data with the intelligent robots to patrol and monitor at a square in order to check the complex situation.The node positioning and the problem for power of BT sensor networks are studied.The design principle of sensor nodes is discussed.The feasibility of adjusting square’s illume state according to the information from sensor nodes is also discussed.Many experiments prove this system is stable and efficient and can be used to check environment or something alike.