A turbulent model of convective mass transfer and a model of internal mass sources resulted by crystallization are presented. The theoretical analysis and numerical calculation are carried out for turbulent convection mass transfer in heated tubes with consi deration of internal mass sources under constant properties. The influence of internal mass sources on the concentration distribution, average concentration of colloidal particals and mass flux on the wall has been analyzed. It has been found that if the mass transfer coefficent in the case with consideration of internal mass sources is defined as Eq.(20), the Sherwood number and mass transfer coefficient in the case with consi deration of internal mass sources are equal to those in the case without consideration of internal mass sources; Under the conditions studied here, I_s<<C_m, the effect of I_s on mass transfer can be neglected; In the case when considering internal mass sources the mass flux may increase gradually along x due to increase of C_m.