OBJECTIVE： To provide a way to evaluate test capability for biological sample analysis laboratory， so as to improve this test quality. METHODS： By analyzing the use of measurement uncertainty in China and detailing the steps of biological sample analysis laboratory measurement uncertainty， the effects of measurement uncertainty on biological sample analysis laboratory are illustrated from two aspects of inner and outer quality control. RESULTS & CONCLUSIONS： National laboratories mainly examine the source of uncertainty through establishing mathematical model， and then uncertainty is evaluated. Uncertainty evaluation is a continuous process. Uncertainty assessment and assurance is the overall situation in a biological sample analysis laboratory quality control. Thus， biological sample analysis laboratory can find a method of self-testing capabilities by uncertainty evaluation， find the maximum uncertainty and eliminate or reduce it gradually， ultimately improve laboratory testing quality.