The research was investigated to explore the effects of two types of earthworm (Eisenia foetida and Metaphire guillelmii) on content and constituent of soil amino acids in lab. The main results were as follows: 1) The content of soil amino acids was modified by addition of earthworm, as the amount of acidic hydrolysable amino acid in soil was increased 5.08 g/kg and 3.86 g/kg by activities of Eisenia foetida and Metaphire guillelmii respectively, and content of free amino acid was enhanced 7.72 mg/kg and 4.44 mg/kg in addition of Eisenia foetida and Metaphire guillelmii respectively. 2) The proportion of neutral amino acid to acid hydrolysable amino was the largest (average 51.9%), the acidic amino acid took the second place (average 23.3%), while the sulfur-containing and basic amino acid made up only 14.4% and 10.4% respectively. So was the free amino acid, as neutral amino acid played the primary part of 54.4%, and basic amino acid accounted just for 7.2%. 3) Earthworm activities did not alter the species of amino acid, of which 16 sorts of acid hydrolysable amino acid and 14 kinds of free amino acid were detected. 4) The constituent content of acid hydrolysable amino acid in soil was affected significantly by the activities of earthworm: with addition of Eisenia foetida, the aspartic acid, arginine, methionine, alanine and lysine were increased above 85.7%, while the valine, threonine, serine, glutamic acid, leucine, tyrosine and histidine had 40.7%-62.7% increasing. In the treatment of Metaphire guillelmii, methionine, lysine, aspartic acid, tyrosine and alanine were enhanced significantly at least 71.9%; glycine, arginine and isoleucine had been increased 56.8%、55.6% and 54.9% respectively; the smallest increasing below 40% appeared in serine, leucine, threonine, glutamic acid, histidine and phenylalanine. 5) Addition of earthworm changed the constituent content of free amino acid obviously in the same time: under Eisenia foetida activities, the histidine, arginine, glycine, leucine, isoleucine and alanine had the greatest growth (more than 150%), but aspartic acid, threonine, serine, valine, glutamic acid and phenylalanine were increased gently of 58.8%-92.1%. Because of addition of Metaphire guillelmii, a significant increasing of 184.2%、173.3%、163.0% and 116.6% appeared in aspartic acid, arginine, serine and isoleucine respectively; The growth of threonine, leucine, valine and glycine were from 52.3% to 92.7%; The increasing of glutamic acid, histidine, phenylalanine, alanine and methionine were below 33.1%, while cysteine decreased significantly with 11.8%. Obviously, two biotypes of earthworm showed the same trend in total and constituent content of soil amino acid, but there are significant differences in intensity. Overall, Eisenia foetida did better than Metaphire guillelmi.