Nano-structured fibers of the synthesized poly(p-dioxanone-co-trimethylene carbonate) (PDT) were prepared by electrospinning technique. Their physicochemical and biological properties were evaluated with the standards for biomedical materials, and it was found that the content of trimethylene carbonate (TMC) units in PDT copolymer could change these properties. As observed by the scanning electron microscopy (SEM), more TMC units in the copolymer would lead to severer fiber bonding, which probably is due to the ductility of TMC segments. The results of static water contact angle testing for the electrospun membranes demonstrated that the hydrophilicity of PDT was between that of PPDO and PTMC. The growth status of L929 mouse fibroblasts on the as-spun membranes of PDT and PPDO was evaluated by the fluorescent micrographs and MTT assay. It was shown that the cells grew well, which suggested good biocompatibility of these copolymers and their suitability in biomedical fields. The in vitro biodegradability of the electrospun membranes in phosphate buffered saline (PBS) and PBS with lipase was separately investigated via measurements of mass loss, M-w retention, as well as variations in crystallinity, thermal properties, pH value, and morphology. After 35 days of degradation, mass and Mw of the polymers significantly reduced while slight differences appeared in pH values before and after. Among the samples, the pH value exhibited the most descent for PBS with PPDO and the least for PBS with PTMC; pH decrement of PBS with PDT was in the middle. These results pointed out that the existence of TMC units in the polymers reduced acidic products in the degradation process, which was good for implanted materials. The changes of SEM images of PTMC at different degradation time indicated that PTMC degraded by surface erosion. And the changes of thermal properties of PDT indicated that PTMC was susceptible to enzymatic degradation by lipase. The lipase enzymatic degradation rate of the polymers containing TMC segments was faster than the hydrolytic degradation rate, which illustrated this point.