NOVELTY - Preparation of high-purity lithium iron silicate (Li2FeSiO4) comprises uniformly dispersing nanosilica in water in the presence of polyethylene glycol to form aqueous solution; adding lithium source, iron source and composite additive; uniformly stirring to form a dry gel; pressing dry gel into cake shape; and calcining in inert or reducing atmosphere. The molar ratio of polyethylene glycol and nanosilica is 100:0.1 to 100:5. The molar ratio of lithium source, iron source and nanosilica is 2:1:1. The molar ratio of composite additive and iron source is 1:1 to 15:1.    USE - Method for preparing high-purity lithium iron silicate (claimed) used as lithium ion battery material.    ADVANTAGE - The method is simple, easy to control and operate, and suitable for large-scale production; and has high capacity ratio when used as lithium ion battery material. The battery assembly is environment-friendly and has high safety and low production cost. The use of trivalent iron reduces production cost. Product stability and consistency is easy to control.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) preparation of high-purity carbon-coated Li2FeSiO4 modified product by uniformly dispersing nanosilica in water in the presence of PEG; adding lithium source, iron source and composite additive; uniformly stirring to form a dry gel; and mixing dry gel, organic material and liquid dispersant, ball-milling, removing dispersant, pressing into cake shape, and calcining in inert or reducing atmosphere; and    (2) preparation of high-purity Li2FeSiO4 doped and coated modified product by uniformly dispersing nanosilica in water in the presence of PEG; adding lithium source, iron source, composite additive and other doping element(s); uniformly stirring to form a dry gel; and mixing dry gel, organic material and liquid dispersant, ball-milling, removing dispersant, pressing into cake shape, and calcining in inert or reducing atmosphere, in which the molar ratio of other doping elements and iron source is 0.01-1:1, and the weight ratio of dry gel and organic material is 95:5 to 70:30.