To evaluate the value of seminal plasma miR-210-3p as a novel and non-invasive biomarker for screening dyszoospermia caused by varicocele. Semen samples from patients with varicocele and healthy males were collected for semen analysis and quantitative real-time polymerase chain reaction. Cox univariate and multivariate analysis and receiver operating characteristic curve analysis were used to assess the relationship between the level of seminal plasma miR-210-3p and impaired spermatogenic function. Our results showed that the level of seminal plasma miR-210-3p in the varicocele patients was 2.18 times that of the control group (p < 0.001), and its expression increased significantly with the severity of varicocele. Compared with preoperative, the expression of seminal plasma miR-210-3p declined significantly at 3 months after surgery. Cox univariate and multivariate analysis showed that seminal plasma miR-210-3p (p = 0.02), bilateral varicocele (p = 0.04) and the grade 3 varicocele (p = 0.03) were significantly and independently associated with dyszoospermia caused by varicocele. Our results suggest that seminal plasma miR-210-3p is a useful clinical biomarker for screening dyszoospermia caused by varicocele, and this is the key to deciding early effective treatment and protecting the fertility of the patients.