The invention relates to lemon essence for water-based ink. The lemon essence is prepared from, by weight, 1%-30% of lemon essence, 5%-55% of compound modification oligosaccharide and deionized water. The lemon essence is composed of lemon oil, litsea cubeba oil, citral diethyl acetal, myrac aldehyde, bergamot aldehyde, lemonile, decanal, caprylic aldehyde, dodecanenitrile, citonellye nitrile, ethyl methylphenylglycidate, linalyl acetate, linalool, lilial, benzyl acetate, cyclamen aldehyde, terpilenol, terpinyl acetate, anisic aldehyde, verdyl acetate, geraniol, geranyl acetate, citronellol, citronellyl acetate, isocyclocitral, styralyl acetate, isoeugenol, ionone, heliotropin, iso-longitolanone, HHCB and ethyl alcohol. The invention further provides a preparation method of the lemon essence for the water-based ink. According to the lemon essence for the water-based ink and the preparation method of the lemon essence, the compound modification oligosaccharide is used as a wall material, the lemon essence is wrapped so that lemon nanocapsule slow-release essence can be formed, and therefore fragrance depositing and water solubility of the essence are improved.