A two-sample Mendelian randomization (MR) study was used to evaluate the potential causal relationship between insomnia and the risk of neurological disorders and tinnitus. Methods: The IEU OpenGWASproject website was used to obtain genome-wide association study (GWAS) data of insomnia and neurological diseases, and the independent single nucleotide polymorphisms (SNPs) closely related to insomnia were screened as instrumental variables (IVs), and SNPs related to neurological diseases were selected as outcomes. Among them, The insomnia data included 462 341 samples, the neurological disease data included 148 552 samples, and the tinnitus data contained 117 882 samples. A total of 42 SNPs closely related to insomnia were selected as instrumental variables. Inverse variance weighted (IVW), weighted median (WME) and MR-Egger methods were used for Mendelian randomization analysis. At the same time, the Egger intercept detection level pleiotropy and the leave-one-out method were used for sensitivity analysis to ensure the robustness of the results. Results: IVW analysis showed a significant positive correlation between insomnia and the occurrence of neurological diseases (OR=2.032, 95% CI 1.567～2.636, P=9.011 × 10-8 ). There was no significant difference between the value of Egger intercept and 0(P=0.803), indicating that there was no horizontal pleiotropy. The leave-one-out method showed that the results were stable, and no SNPs with a large impact on the results were detected. All F-scores greater than 10 indicate no weak IVs bias. IVW analysis showed that there was a positive correlation between insomnia and tinnitus (OR=1.056, 95%CI 1.009～1.104, P=0.019). There was no significant difference between the value of Egger intercept and 0(P=0.985). The leave-one-out method showed that the results were stable, and no SNPs with a large impact on the results were detected. All F-scores greater than 10 indicate no weak IVs bias. Conclusion: There is a positive causal relationship between insomnia and the occurrence of neurological diseases, and there is also a positive causal relationship between insomnia and tinnitus.