End pumping is a simple pumping method in double clad fiber laser. According to rate and heat conduction equations, the distribution of power and temperature in end pumped Yb3+ doped double clad fiber laser is studied. It is shown that the maximum output power can be obtained for backward pump, the distribution of temperature in fiber is the flattest for bidirectional pump, when no severe thermal effect happens, higher laser power can be obtained for backward pump, when fiber laser works at high power level, thermal effects can be reduced for birectinal pump, and backward pump power can be properly increased to acquire higher laser power. The results provide a good reference for designing end pumped high power double clad fiber laser.