Fatigue behavior of newly developed Eco AZ31, AM30 alloy was investigated. Microstructure analysis, tensile test, high cycle fatigue test, fatigue crack propagation were conducted in this study. Observation of micro structure identified Eco magnesium alloy (Eco AZ31, Eco AM30) had a finer crystal grain size compared to the comparison material. AZ31 (comparison material) and ECO AZ31 alloy all featured Mg17Al12, Al6Mn and Mg32(Al,Zn)49 phases in Mg matrix, and AM30 (comparison material) and ECO AM30 alloys all featured Mg matrix and Mg17Al12, Al6Mn phases. In addition to the crystal grain, Al2Ca phase was identified in ECO magnesium alloys (AZ31, AM30). Eco magnesium alloys (AZ31, AM30) all had finer, more even reinforced phases compared to existing comparison material alloys. In a tensile test, Eco magnesium alloys (AZ31, AM30) featured higher tensile and yield strengths compared to comparison material alloys, and the elongation rate also increased by a little. Fatigue test revealed that Eco alloys had singnificantly improved fatigue life(characteristics) in all stress conditions compared to comparison materials. However, fatigue crack propagation test (da/dN vs. ?K) revealed that Eco magnesium alloy (AZ31, AM30) had similar, but slightly lower fatigue crack propagation resistance compared to comparison materials. With foundation of fracture surface observations after tensile, high-cycle fatigue and fatigue crack propagation test, the improved tensile characteristics, higher high-cycle fatigue characteristics and slightly reduced fatigue crack propagation resistance characteristics of the Eco magnesium alloys motioned above are suspected to be the product of the alloy’s micro structure elements featuring finer crystal grains and evenly distributed reinforced phase.