the present invention belongs to the biomedicine field and specifically concerns an enzyme - degradable polymer and the application thereof . to solve the problem of low sensitivity of the existing assay reagents , the present invention provides an enzyme - degradable polymer and the related application of the polymer . the present invention also provides hydrogels , nano - particles , fluorescent dye - labeled enzyme substrates and kits for detection or activity - analysis of biological enzymes based on the enzyme - degradable polymer . the formula of the enzyme - degradable polymer is p 1 - n - n - x x = wherein , n is a non - enzyme substrate domain , the n aa may be different , and n is a non - negative integer ; n is an enzyme substrate domain , the n aa may be different , and n is a non - negative integer ; p 1 is a protecting group of α - amino or functional group ; p 2 is a protecting group of α - amino ; p 3 is — nh 2 , a small molecule compound or a fragment of a polymer .