The(La

0.7

Mg

0.3

)Ni

x

（x=2

2.5

3）hydrogen storage alloys were prepared by negative pressure induction melting

and the hydrogen storage properties

phase composition and microstructure of rapidly quenched and ingot(La

0.7

Mg

0.3

)Ni

x

hydrogen storage alloys before and after annealing were analyzed comparatively.The results reveal that with the increase of Ni content in(La

0.7

Mg

0.3

)Ni

x

alloy

hydrogen releasing platform of the rapidily quenched hydrogen storage alloy is increased gradually and the platform is tended to be wider

and the rate of hydrogen release and the capacity of the hydrogen release are increased gradually.Plateau pressure of(La

0.7

Mg

0.3

)Ni

2.5

alloy is moderate with relatively better platform performance.When x=2.5

the ingot hydrogen storage alloy has relatively wider and flatten hydrogen absorption and desorption platform compared with hydrogen storage alloy with x=2.In addition

Ni content increase is beneficial to improving the hydrogen releasing rate of the alloy.The phases of ingot and rapidly quenched(La

0.7

Mg

0.3

)Ni

x

hydrogen storage alloys are all composed of LaNi

5

（LaMg）Ni

3

and（LaMg）

2

Ni

7

phases at the as cast and annealed state at different temperatures

and with the increase of annealing temperature

LaNi

5

and（LaMg）Ni

3

phase has the characteristics of transition toward（LaMg）

2

Ni

7

phase.