The invention relates to environment-friendly and low-temperature residue-free solder paste and a preparing method thereof. According to the technical scheme, the environment-friendly and low-temperature residue-free solder paste is characterized in that the solder paste comprises, by weight, 41.0%-60.0% of Sn, 26.6%-37.7% of Bi, 2.1%-4.4% of a third element alloy and 9.0%-19.0% of scaling powder; and the scaling powder comprises, by weight, 67.0%-75.0% of a carrier, 14.8%-18.8% of an activating agent, 4.6%-8.72% of a thixotropic agent, 0.32%-3.2% of a surface active agent and 1.48%-3.5% of corrosion inhibitor. The environment-friendly and low-temperature residue-free solder paste is provided, halogen-free components are adopted in a formula, volatile components are avoided in the tin paste, and smells are avoided during using. After welding, residues are colorless and transparent, and the effect of replacing Pb containing tin paste or halogen-containing tin paste is achieved. Under the low-temperature welding condition, nano aluminum powder is added, a high-temperature solid solution is formed during welding to serve as an auxiliary part for supplementary welding, poor welding of a Sn-Bi alloy is effectively improved, and the welding requirement for aluminum components on the surface of an electronic component can be met; and meanwhile, the storage period of the tin paste is prolonged, and better wettability is brought.