Objectives To assess the effect of thoracic paravertebral block (PVB) on pain management and preservation of pulmonary function compared with intravenous, patient-controlled analgesia (IVPCA) in patients with multiple rib fractures (MRFs). Methods Ninety patients with unilateral MRFs were included in this prospective study and randomly assigned to the TPVB or IVPCA group. The visual analogue scale (VAS) pain score, blood gas analysis, and bedside spirometry were measured and recorded at different time points after analgesia. Results TPVB and IVPCA provided good pain relief. VAS scores were significantly lower in the TPVB group than in the IVPCA group at rest and during coughing ( P < 0.05). Patients in the TPVB group had a higher PaO2 and PaO2/FiO2 and lower P(A–a)O2 compared with the IVPCA group ( P < 0.05). Moreover, patients in the TPVB group showed higher FVC, FEV1/FVC, and PEFR, and fewer complications than did the IVPCA group ( P < 0.05). Conclusion TPVB is superior to IVPCA in pain relief and preservation of pulmonary function in patients with MRFs.