Abstract: In order to obtain the effect of temperature on the separate spatial soliton pairs in an unbiased series photorefractive crystal,the low-amplitude bright-dark separate spatial soliton pairs in an unbiased series photorefractive crystal circuit are investigated theoretically.The analytical solutions for both bright and the dark low-amplitude separate spatial soliton in series photorefractive crystal circuit are obtained.The effect of temperature on the soliton property is analyzed.The result shows that the dynamical evolution of bright soliton in one crystal can be modulated by changing the temperature of the other crystal in which the dark soliton is supported.The dynamical evolution of the bright-dark separate spatial soliton pair is investigated by numerical simulation.Potential application in thermo-control optical devices is discussed.