Abstract: This study starts with the structure of digital resources procurement contract. It analyses the existing preferences and blind areas of libraries in the current digital resources procurement, further expounds the causes and importance of the terms of subject packages, and points out that the purchase of subject packages is essentially the result of a specific contract concluded by the high sales strategy of database providers and the pursuit of low selection cost of libraries in the interests of win-win. The contract structure of 11 journal databases jointly collected by DRAA is analyzed. The number, price and variety of subject packages are studied. Three indexes are designed—degree of freedom F, zero integral ratio coefficient P, and repetition rate coefficient Q—to scientifically reflect the rationality and scientificity of the contract, which provides a quantifiable reference standard for the standardization of digital resource contracts.