The mathematic models of two-dimensional heat and mass transfer for lithium bromide （LiBr）aqueous solution added nano-particles are developed and validated by experimental data. The research results show that: the nano-particles can significantly improve the water vapor absorbing rate of the nano-fluid and the water vapor absorbing rate is increased with the amount of added nano-particles;with the same amount of nano-particles

the water vapor absorbing rate is increased with the flow rates of the nano-fluid and the water vapor absorbing rate as a function of flow rates shows logarithmic curve pattern; the mass transfer enhancement factor is increased with the increasing amount of nano-particles; the mass transfer coefficient of absorber is increased with the amount of added nano-particles;with the flow rate (1.2 L/min) of nano-fluid the mass transfer coefficient increased 1.32 and 1.41 times for adding 0.05% and 0.1% nano-particles respectively

but the amplification is reduced with the increasing of nano’svolume.