The electrical conductivity (s) and Seebeck Coefficient (S) of the solidified melt of lithium based superionic system Li3BO3 : xLi3PO4 (with x = 0,0.33, 0.50, 0.67, 1.0, 1.5 and 2.0) are presented in the temperature range 450 to the melting point of each solid. The ionic (si) and electronic (se) contribution towards the electrical conductivity (s) have been separated over the entire temperature range with the time dependence study of d.c. electrical conductivity (sdc). In all the studied solids superionic phase have been observed below their melting points and conductivity is purely ionic in that phase. The phase transition temperature (Tp) at which solid undergoes from normal to superionic phase has been obtained. It has been shown that these solids are mixed conductor in normal phase. The variation of both the si and se with the temperature are presented and conduction mechanism have also been discussed.