Objective To analyze the effect of unilateral lumbar anesthesia with hypobaric ropivacaine hydrochloride on hemodynamic parameters and incidences of adverse reactions in elderly patients with hip surgery. Methods A total of 98 elderly patients undergoing hip surgery in our hospital were selected and randomly divided into two groups, with 49 cases in each group. The control group were given hyperbaric ropivacaine hydrochloride for spinal anesthesia, while the experimental group were given hypobaric ropivacaine hydrochloride. Then, the hemodynamic changes （MAP and HR） before and after anesthesia, sensory block, onset time and maintenance time of anesthesia, as well as the incidences of adverse reactions of patients were recorded. Results The onset time, block time, and maintenance time of anesthesia of the experimental group were shorter than those of the control group （P<0.05）. The Bromage score of the control group was 2.13±0.86 and that of the experimental group was 2.89±0.23, and the difference was statistically significant （P<0.05）. After anesthesia, the onset of motor block of the control group was slower than that of the experimental group, and the maintenance of anesthesia of the experimental group was longer than that of the control group （P<0.05）. After anesthesia, the experimental group showed less declines in MAP and lower incidences of adverse reactions than the control group did （P<0.05）. Conclusion Unilateral spinal anesthesia with hypobaric ropivacaine hydrochloride features quick onset, long duration of anesthesia, perfect analgesia, few side effects, and few hemodynamic changes in elderly hip surgery, thus it is worth promoting.