A liposome for delivery of nucleic acid is provided herein, comprising cationic lipid compound, a phospholipid and a PEGylated lipid, wherein the cationic lipid compound is in an amount from 50 wt % to 90 wt % and consist of a lipid compound and a cholesterol lipid compound. A nucleic acid liposome formulation comprising the said liposome and the nucleic acid encapsulated by the liposome and the method for preparing the same are provided therein. Increased amount of nucleic acid can be loaded into the nucleic acid liposome formulation as described therein. Thus, at the same dosage, intake of the cationic lipid compound is decreased, thereby decreasing toxicity.
