By measuring threshold and using traveling wave amplification, the small signal gain coefficient and storage efficiency of a novel multi –slab Nd:glass laser amplifier designed and fabricated by us have been determined experimentally. It has been shown that a storage efficiency of 3.84% has been achieved in the use of this amplifier, which is higher than that of the conventional amplifier. Furthermore, the multi –slab laser amplifier has the potential advantage of providing the high power and good beam quality.