Poly(propylene fumarate-co-propylene sebacate) (P(PF-co-PS)) was crosslinked with N-vinyl pyrrolidone (N-VP) to form networks. It was investigated as biodegradable bone cement. In this paper, P(PF-co-PS) was synthesized and characterized by 1 H-NMR, FTIR and GPC. The effects of the amount of sebacate segments in P(PF-co-PS) main chains and the quantity of N-vinyl pyrrolidone on the in vitro degradation of the polymer networks were examined. Cylindrical specimens were submerged in phosphate buffered saline (PBS) at 37 ℃ and the pH value of PBS is 7.4 for 10 weeks. The gravimetry and compressive mechanical properties were tested over the degradation period. Networks formed by P(PF-co-PS)8020/N-VP exhibited higher weight loss and better mechanical properties when compared with poly(propylene fumarate)/N-VP networks. The mechanical properties of P(PF-co-PS)/N-VP can be maintained for a very long time, even for 70 days, the yield strength, fracture strength and compressive modulus are (51.78 ± 2.01) MPa, (52.331 ± 1.84)MPa and (957.78 ± 24.40) MPa, respectively. The results demonstrate that the compressive mechanical properties and degradation velocity can be modulated by the amount of crosslinking agents and sebacate segments along the main chains of copolymers.