Background: MicroRNAs serve a crucial role in the post-transcriptional control of gene expression, as well as in development and cellular activities. Differential miRNA expression patterns between osteoarthritis (OA) patients and healthy persons demonstrate the significance of miRNAs in the pathogenesis of OA. miR-34a-5p affects biological activities such as p53-induced cell cycle arrest, apoptosis, and senescence, and its expression is markedly elevated in the plasma of patients with advanced primary knee osteoarthritis (KOA) Methods: The expression of miR-34a-5p in human plasma (n = 60) was measured using quantitative real-time PCR, all subjects were divided into two groups: Group (A): Forty primary KOA patients who met the American College of Rheumatology (ACR) criteria .Group (B): Twenty healthy individuals. They were of the same age and gender as OA patients. Results: Our research demonstrated that miR-34a-5p expression is considerably elevated in the plasma of patients. Conclusion: Our study illustrates the function of miR-34a5p in the pathogenesis and joint destruction of primary KOA.