Purpose <p>The corneal biomechanical characteristics of pterygium were observed at different stages of disease progression and before and after surgery.</p> Methods <p>This prospective, nonrandomized controlled study enrolled 175 patients who underwent pterygium excision combined with limbal conjunctival autograft for unilateral pterygium. They were divided into the small-pterygium (SP) group with 75 cases (75 eyes), the massive-pterygium (MP) group with 100 cases (100 eyes), and the contralateral normal eye group (control). The biometric parameters were measured with IOL Master; the length and area of pterygium, with Image J; and the corneal biomechanical parameters pre-surgery and one month post-surgery, with Corvis ST. Predictive factors for corneal biomechanical changes in pterygium were assessed, and a receiver operating characteristic curve was plotted using multifactor logistic regression analysis.</p> Results <p>Comparison of preoperative corneal biomechanical parameters between two groups of pterygium patients showed that the MP group had a lower Ambrósio’s relational thickness horizontal (ARTh) and a larger Peak Distances (PD) than the SP group (<i>p</i> = 0.000). Preoperatively, both groups showed significant increases in second applanation time (A2T) and integrated radius (IR), and a decrease in ARTh (<i>p</i> &lt; 0.05) compared with the control, with greater changes in the MP group than in the SP group. In the MP group, the preoperative first applanation length (A1L), second applanation length (A2L), and IR increased, while the first applanation time (A1T) and second applanation velocity (A2V) decreased compared with the control (<i>p</i> &lt; 0.05). Postoperatively, A2T, PD, and IR significantly decreased (<i>p</i> &lt; 0.05). In the MP group, postoperative A1L and deformation amplitude (DA) also significantly decreased compared with preoperative; A1T, A2V and ARTh increased (<i>p</i> &lt; 0.05); and A2T and IR remained significantly higher, while ARTh was significantly lower than in the control (<i>p</i> &lt; 0.05). The SP group showed no statistically significant postoperative differences in corneal biomechanical parameters relative to the control group (<i>p</i> &gt; 0.05). Overall, the MP group had a greater impact on biomechanical parameters than the SP group, and recovery was less complete. The horizontal diameter (HD) of the pterygium invading the cornea, the vertical diameter (VD) covering the corneal limbus, and the area invading the cornea (PA) were positively correlated with PD (<i>p</i> &lt; 0.05). PD was significantly associated with corneal biomechanical recovery (<i>p</i> &lt; 0.05).</p> Conclusion <p>Pterygium alters corneal biomechanics. Larger pterygia produce greater corneal biomechanical variability. These changes can be partially improved but not completely reversed through surgical treatment. PD may serve as a new predictive indicator for corneal biomechanics in pterygium.</p>