A monitoring strategy for visual navigation in multi-object environment with only one PT(Pan-Tilt) camera based on rough set theory under finite-state machine frame is proposed.The model to estimate the reliability level of multi-object orientation and an algorithm to calculate the objects priority are defined firstly.Then a finite-state machine model to monitoring each object is put foreword.A minimal rule set for monitoring multi-object is achieved by using reduction algorithm of rough set theory.Also a description method of reduction based on not-value property is proposed which is not included in the classical rough set theory.The validity and practicability of the strategy are proved by the experiments accomplished by using autonomous mobile robots to finish certain tasks in multi-object environment.