Compared to conventional PV/T solar collector, the bi-fluid PV/T type enables to extract more heat producing hot air and hot water and thus increasing the total efficiency per unit of area. The use of both fluids leads to provide a variety of PV/T thermal applications. In this paper, a mathematical modeling of a bi-fluid photovoltaic/thermal PV/T solar collector type is developed and simulation was performed using MATLAB software. Furthermore, a performances comparison is carried out for four bi-fluid PV/T collectors using different cooling fluid (eg.air,water) in simultaneous operating mode. In this context, the temperature distribution in different collectors layers, electric power generation efficiency and thermal power efficiency are evaluated and analyzed. According to obtained results, water-water cooled PV/T collector proves a good effectiveness and reaches a higher electrical and thermal efficiency respectively of 11.16 and 54.22%. This bi-fluid type is considered as the most provider of hot water in contrary to Air air cooled PV/T witch providing more hot air.