In order to study the effects of different tensile processes on the crystal structure and macroscopic properties of biaxially oriented polylactic acid (BOPLA) films, BOPLA films were prepared by extrusion casting process, and the stretching test was carried out by using a film biaxial stretching testing machine to change the stretching process. The crystalline, mechanical, barrier and optical properties of the films were investigated. The results show that with the increase of the stretching ratio, the PLA film crystallization induced by tensile increased to 37.84%, which was nearly three times higher than that of the 1×1(unstretched) BOPLA film, and the glass transition temperature (Tg) increased to 65.32℃. The longitudinal (MD) and transverse (TD) tensile strengths increased to 84.47, 93.44 MPa, respectively, while the maximum elongation at break was 39.81% and 42.29% at 2×2 stretching ratio, respectively. With the increase in stretching temperature, the thermal movement of molecular chain accelerated, the diffusion rate of chain segment to the crystal nucleus and the rate of regular stacking increased, and the crystallization rate accelerated and the relative crystallinity increased up to 48.99%. Moreover, heat-induced crystallization promoted the formation of more complete crystalline forms (α crystalline forms). The oxygen barrier property of PLA film was improved by increasing the stretching temperature. The oxygen barrier coefficient decreased to 8.61×10-16 cm3·cm/(cm2·s·Pa) at 130℃, which was 59.7% lower than that at 80 ℃, but the tensile strength and elongation at break showed a decreasing trend, since rapid chain relaxation would promote the molecular chain disorientation, limit the strain induced crystallization, and destroy the molecular chain entanglement network. With the increase in the stretching rate, the orientation and crystallization of the amorphous chain were enhanced, and the elongation at break along the MD direction of the film was greatly increased to 37.62% only at 600%/s.