Texturing is carried out on synthetic filament yarns to achieve appearance and physical characteristics similar to spun yarns. These characteristics are affected by processing parameters and supply yarn properties. We have produced pin and air-jet textured (PAT) yarns and air-jet textured (AT) yarns with different processing parameters, such as overfeed ratio and air pressure, to characterize the splitting behavior and physical properties of split-type microfine polyester/nylon (P/N) filament yarns. PAT and AT yarns had more loops and entanglement formation with increase in overfeed and air pressure, and it was shown that the PAT yarns had more compact at the yarn core and exhibited a greater number of loops than the AT yarns. The fiber splitting of RAT and AT yarns occurred at 10% overfeed, 7kg/$ extrm{cm}^2$ and 20% overfeed, 8kg/$ extrm{cm}^2$, respectively. The tenacity and breaking extension of two ir-jet textured yarns were generally reduced with the increase of overfeed and air pressure as compared with those of supply yarns. But the tenacity of AT yarns was generally higher than that of PAT yarns, while the braking extension of AT yarns was lower than that of PAT yarns, as the overfeed and air pressure were increased. The instability of PAT and AT yarns increased with increasing overfeed and air pressure. But the instabilities of PAT yarns were higher than those of AT yarns.