Abstract: Nd3+:NaGdF4 nanocrystals dispersed in dimethyl sulfoxide is taken as the green liquid laser medium. Constructing side-pump configuration and transverse liquid flow system, the stable thermal flow field distributions are analyzed by ANSYS software. The results show that when the shape of the flow channel, the flow regime, and the wall surface remain unchanged, the thermal flow field distributions of the liquid are basically the same, and the frequency of pump light has a little effect on streamline distribution; the velocity of the input liquid will affect the distribution of the streamlines, the higher the velocity of input liquid is, the greater the streamline density is. Following the flow direction, the temperature of the medium in the pump area gradually increases, and in the area with constant flow direction of liquid, the temperature distribution is relatively uniform.