The present disclosure relates to a copper based microcrystalline alloy and a preparation method thereof, and an electronic product. In percentage by weight and based on the total amount of the copper based microcrystalline alloy, the copper based microcrystalline alloy includes: 30-60 wt % of Cu; 25-40 wt % of Mn; 4-6 wt % of Al; 10-17 wt % of Ni; 0.01-10 wt % of Si; and 0.001-0.03% of Be.