Abstract: The purpose of this paper is to explore the characteristics of fracture instability of engineering rock mass under combined acoustic emission and deformation field monitoring and analyze the internal relationship between them and rock fracture instability.In this paper, the uniaxial compression test of gneiss is carried out to provide a more comprehensive method for early warning.The results are as follows:there is little time difference between the start points of the acoustic emission cumulative ringing count and the strain mean square deviation of the deformation field, while there is a big time difference between the warning points.On the whole, the acoustic emission detects the rupture information earlier than the deformation field.The cumulative acoustic emission ringing count curve and strain mean square deviation curve can give warning when the near vertical slope rises sharply for the first time, indicating that the rock is about to collapse.The cumulative acoustic emission ringing count curve increased by 20%-50%, accounting for 34.65% on average, and the strain mean square deviation curve increased by 25%-65%, accounting for 41.15% on average.In terms of the early warning of rock fracture and instability, the temporal acoustic emission is earlier than the deformation field, but the deformation field can be used to observe the rock surface crack evolution in real time.By combining the two monitoring methods, the rupture of engineering rock mass can be understood more comprehensively, and the theoretical basis for stability control and prevention of engineering rock mass can be provided.