<div class="htmlview paragraph">In this paper from the comparison of the results of three fatigue tests on almost 60 specimens of different materials, it is concluded that the effects of the F-by-F random load spectrin (hereinafter the random spectrum) and the block load spectrum (hereinafter the block spectrum) on the fatigue life scatterance are basically the same and no much difference, and that the scatter factor of fatigue lives under either spectrum must be the same. This conclusion is different from those in the preceding references (<span class="xref">1</span>)(<span class="xref">2</span>).</div>