Low oral bioavailability of alendronate sodium (ALE) significantly limits its clinical application. However, few studies focus on preparing ALE solid lipid nanoparticles (ALE-SLNs) and investigating its oral bioavailability in vivo due to highly hydrophilic property of ALE. In this study, ALE-SLNs were prepared through high-speed shearing combined with ultrasonic treatment method. ALE-SLNs were evaluated by average particle size, electric potential, encapsulation efficiency (EE), and drug loading (DL). Our results showed that the average EE and DL reached 62.56±0.94% and 6.26±0.09% (n=3), respectively. 120.27±1.17nm, 0.29±0.13 and -19.1±0.27 mV (n=3) were obtained in the average particle size, polydispersity index and zeta potential, respectively. The stability test showed that ALE-SLNs remained stable for more than 2 months at 4°C. After oral administration of ALE-SLNs (4.5mg/kg), the bioavailability was 2.17 times higher than that of ALE solution (86.82±3.6 vs 40.1±1.3μg) in rats. Our results indicate that high-speed shearing combined with the ultrasound method is simple and rapid to prepare ALE-SLNs. SLNs can improve the oral delivery of ALE in rats, which may exert beneficial effects in clinical applications.