Objective To observe the safety and effectiveness of ropivacaine combined with hydromorphone on paravertebral nerve block in thoracoscopic surgery. Methods A total of 76 patients, American Society of Anesthesiologists (ASA) Ⅰ or Ⅱ, aged 30‒65 years, who underwent elective lung cancer surgery were enrolled. According to the random number table method, they were divided into two groups (n=38): a ropivacaine group (group C) and a ropivacaine combined with hydromorphone group (group H). Their onset time of nerve block, duration of analgesic effect, and the amount of perioperative sufentanil were recorded. Their Visual Analogue Scale (VAS) and Bruggrmann Comfort Scale (BCS) scores at the time when they returned to the ward from the post-anesthesia care unit (PACU) (T0), and 6 h (T1), 12 h (T2), 24 h (T3), and 48 h (T4) after they returned to the ward were recorded. The effective pressing times of analgesic pump, the number of rescue analgesia, the number of postoperative skin itching, nausea and vomiting, dizziness, urinary retention and constipation were also recorded and compared. Results Group H presented shorter onset time of nerve block than group C (P<0.05), and longer duration of analgesic effect than group C (P<0.05). The amount of perioperative sufentanil, the effective pressing times of analgesia pump and the number of rescue analgesia in group H were less than those in group C (P<0.05). Group H showed lower VAS scores at T1 and T2 than group C (P<0.05), and higher BCS score than group C (P<0.05). There was no statistical difference in the number of postoperative skin itching, nausea and vomiting, dizziness, urinary retention and constipation (P>0.05). Conclusions The combined use of ropivacaine and hydromorphone is safely for paravertebral nerve block, which can accelerate onset time and prolonging analgesic effect.