[Objective]This study aimed to establish an effective method for evaluating uncertainty in determination of reducing sugar content in sugarcane with Lane-Ernon method.[Method]Based on analysis of the main sources of uncertainty in determination of reducing sugar content in sugarcane and mathematical model construction,combined uncertainty and expanded uncertainty were determined to establish the method for evaluation of uncertainty in determination.[Result]Among uncertainties in determination of reducing sugar content in sugarcane with Lane-Ernon method,the greatest uncertainty was introduced by duplicate determination.According to results of statistical analysis,the expanded uncertainty in determination of reducing sugar content was 0.012%.[Conclusion]This study provided theoretical reference for evaluation of uncertainty in determination of reducing sugar content in sugarcane.