The currently developed small-diameter vascular grafts have compliance mismatch against the adjacent native artery, which causes occlusion and other problems. This study thus produces polylatic acid (PLA) tubular knits to serve as small-diameter vessel grafts, and explores the compliance and biocompatibility of the knits after thermal treatment. 150 Denier (D), 225D, and 300 D polylactic acid filaments with good biocompatibility are respectively made into PLA tubular knits with two knit structures, forming six types of circular knits. Six knit types are then observed by a stereomicroscope, and evaluated for porosity, longitudinal tensile strength, circumferential property, biocompatibility, and toxicity. The test results indicate that a high fineness (D) of PLA fibers improves the tensile strength of PLA tubular knits. Moreover, PLA fibers with a fineness of 300D have distinctively decreased compliance. The MTT results suggest that PLA tubular knits is biocompatible with the L929 cells.