A method for preparing nano-silver powder dispersible in environment friendly weak solvents, and an electrically conductive ink comprising the nano-silver powder are disclosed. The disclosure describes a disperser dissoluble in water and weak solvents and an alcohol amine as reducing agent to prepare mono-dispersed nano-silver, and employs ultrafiltration for purification and spray drying process to obtain a nano-silver powder dispersible in weak solvents, and thereby obtain an eco-solvent nano-silver electrically conductive ink. The electrically conductive ink in accordance with the disclosure has advantages of high safety, low volatility, low toxicity, high flash point, resistant to ultraviolet radiation and moisture etc., and can be used with uncoated bearing substrates, and is suitable for use in outdoor environments.