Free-space optical communications (ultraviolet and infrared communications) have emerged as a viable alternative to RF communication for many applications.Ultraviolet communication system even can provide non-line-of-sight links by exploiting atmospheric scattering of light.Atmospheric turbulence can causes fluctuations in the intensity of the received signal,impairing link performance.Many theoretical models about atmospheric turbulence have been proposed to describe turbulence- induced intensity fluctuations.Though some models are simple to implement,they are often used to model some turbulence conditions.Others have excellent fit with measurement data for a wide range of turbulence conditions,but they are complex and difficult to implement.In this paper,we present an adaptive method to select the different simple turbulence model based on the scintillation index in different turbulence conditions and detect the signals in the Poisson and Gauss regime,when the light fluctuations exit in ultraviolet and infrared communication.