After non - continuous (aging 8h and interrupt 16h) and continuous ageing test, the pH values, tensile strength, and degree of polymerization (DP) of acid - and alkaline - paper was tested. The depolymerization rate constant of various ageing test was calculated by the number average degree of polymerization in different times. Results indicate that under the non - continuous ageing test, the paper's pH values, tensile strength, and DP decreased faster than those of the paper under the continuous ageing test. The rate constant of various paper and under different ageing test was KA = 10. 75 x 10-3, KB = 16. 78 x 10-3, Kc = 3. 75 x 10-3, and K0 = 8. 36 x 10-3, respectively. The fluctuation of temperature can facilitate the aging of paper, so the paper should be conserved under the constant environment condition. The results confirm the significant role of alkaline reserve in paper for slowing the degradation processes induced by different accelerated methods.