The invention relates to concentration emulsified diesel fuel, in particular to concentration emulsified diesel fuel long in shelf life and low in cost and a preparation method thereof. The concentration emulsified diesel fuel is prepared through the following raw materials, parts by weight, 20-40 parts of diesel fuel, 16-22 parts of oleic acid, 5-12 parts of methanol, 2-6 parts of sodium nitrate, 26-36 parts of water, 5-14 parts of ethanolamine, 0.3-0.8 part of isooctyl nitrate or amyl nitrate and 0.3-0.8 part of ethylene glycol. Color and transparency of the concentration emulsified diesel fuel are the same as the diesel fuel, shelf life is long, emulation of the emulsified diesel fuel placed for more than 7 years can not be broken, stability is good, and a phenomenon of stratification of oil and water does not occur after the concentration emulsified diesel fuel is placed for 7 years. Through testing data verification, sulphur content is low, water content is high, production cost is greatly reduced, preparation process is simple, and corrosion level is low. The concentration emulsified diesel fuel is low in sulphur content and kinematic viscosity and can enable the diesel fuel to be burned completely when used as a diesel fuel additive, therefore emission quantity of harmful gas is reduced.