The invention discloses a preparation method for a low-temperature nanometer 
lithium iron phosphate cathode material. The preparation method comprises the following steps of: adding a 
lithium source compound, a 
ferric source compound, a phosphorous source compound and water according to a proportion for mixing, adding 
metal ion doped oxide and a primary 
carbon source for mixing, performing primary high-energy superfine pulverization for 2 to 3 hours, performing spray-
drying to obtain 
powder, and performing sieving; pre-treating the 
powder in an 
inert atmosphere at the temperature of 300 to 500 DEG C for 2 to 10 hours, performing cooling, adding a secondary 
carbon source and water, stirring the mixture, performing secondary high-energy superfine pulverization to obtain spherical 
powder, and performing sieving; and performing jet milling on the spherical powder, performing treatment in the 
inert atmosphere at 500 to 600 DEG C for 6 to 30 hours, performing 
thermal treatment at the high temperature of 600 to 900 DEG C for 10 to 30 hours, and performing cooling to obtain the low-temperature nanometer 
lithium iron phosphate cathode material with the 
granularity of 60 to 70 nanometers. When the low-temperature nanometer 
lithium iron phosphate cathode material is used for manufacturing the 
anode of a 
lithium ion battery, the battery has high low-temperature 
discharge performance.