Background and objectives: Objective, accurate, and intuitive evaluation of knee joint function in patients with knee osteoarthritis (KOA) is important. This study aimed to clarify the gait characteristics of patients with bilateral KOA and their correlation with Western Ontario and McMaster University Osteoarthritis Index (WOMAC). Materials and Methods: 20 patients with bilateral KOA and 20 conditionally matched healthy individuals were enrolled in the experimental and control groups, respectively. Footscan and CODA motion gait analysis systems were used to analyse the gait parameters. Gait spatiotemporal parameters and knee joint motion parameters were collected. Weight-bearing balance and walking stability were assessed using discrete trends of relevant gait indicators. Patients in the experimental group were evaluated using WOMAC. Pearson’s correlation analysis was performed on the gait data and WOMAC score data of the experimental group. Results: Velocity, cadence, step length, and stride length of the experimental group were significantly lower than those of the control group (p < 0.01). Step time and gait cycle were significantly greater in the experimental group than in the control group (p < 0.01). Total stance and double-stance times of the experimental group were significantly greater than those of the control group (p < 0.01), whereas the single-stance time was shorter than that of the control group (p < 0.01). The range of motion and maximum flexion angle in the experimental group were significantly lower than those in the control group (p < 0.01), and the minimum angle of knee extension was greater than that in the control group (p < 0.01). The discrete trend of weight-bearing balance and walking stability gait index in the experimental group was greater than that in the control group. The WOMAC score and gait analysis were significantly correlated (p < 0.05). Conclusions: The gait function of patients with KOA is significantly worse than that of normal people. The WOMAC scale and gait analysis can be used to assess KOA severity from different perspectives with good consistency.