A strained Ge-on-insulator structure is provided, comprising: a silicon substrate, in which an oxide insulating layer is formed on a surface of the silicon substrate; a Ge layer formed on the oxide insulating layer, in which a first passivation layer is formed between the Ge layer and the oxide insulating layer; a gate stack formed on the Ge layer; and a channel region formed below the gate stack, and a source and a drain formed on sides of the channel region, in which the source and the drain are a SixGe1-x:C source and a SixGe1-x:C drain respectively to produce a tensile strain in the channel region, in which x is within a range from 0 to 1 and a content of C is within a range from 0 to 7.5%. Further, a method for forming the strained Ge-on-insulator structure is also provided.