This paper presents the research progress of high efficiency and compact all-solid-state lasers based on Yb:YAG slab at room temperature. The laser dynamics model of Yb slab at room temperature is established. It is quantitatively analysed that the pumped laser intensity and the injected laser brightness influence the optical conversion efficiency. The method to suppress the slab-edge-effect is founded. The output power of 22.3 kW, the optical conversion efficiency of 36%, and the beam quality of 2.4 times diffraction limit, were achieved in experiment. These results lay a foundation for the key technology research of higher power laser and development of the miniaturized, lightweight and practical high power Yb slab laser.