The invention discloses a copper-based microcrystalline alloy, a preparation method thereof and an electronic product adopting the copper-based microcrystalline alloy. The copper-based microcrystalline alloy contains the following components of, by taking the total amount of the copper-based microcrystalline alloy as a base and by weight, 30-60% of Cu, 25-40% of Mn, 4-6% of Al, 10-17% of Ni, 0.01-10% of Si, 0.001-0.03% of Be and 0.01-3% of Sn. The copper-based microcrystalline alloy has relatively good mechanical properties, and also shows obviously improved corrosion resistance; and accordingto the copper-based microcrystalline alloy, the flowing property is good, the formability is relatively good, moreover, the copper-based microcrystalline alloy can be processed by adopting a die-casting process so that the surface precision of the product can be remarkably improved, and the copper-based microcrystalline alloy is suitable for preparing an appearance decorating piece with relatively high requirement on the surface precision.