In order to study the key problems of rep-rated high power laser-diode-pumed Yb:YAG laser,a 10 Hz joule-class V-shaped water-cooled Yb:YAG oscillator with active mirror(AM) configuration is demonstrated. An efficient hollow duct coupling system for 12 kW LD was designed and the coupling efficiency is 90%. 3.3 J /10 Hz output energy with 27.5% optical-optical efficiency has been achieved in free running regime,which shows that the thermal effects within the Yb:YAG crystal are well managed by the cooling system of the laser head compared with 4.4 J /1 Hz output energy. The experimental results about two kinds of pumping architectures show that the front-pumped architecture is less effective to decrease the average temperature and its gradient within the gain medium than the rear-pumped architecture which accords basically with our prediction,but the front-pumped is more efficient and has no dichromatic coating′ issues which are helpful to be implemented easily.