The construction characteristics

water absorbability and waterproof mechanismof waterblocking tape used in optical fiber cable are introduced briefly at first. On thesetheory basises

we propose a convenient and effective method--viscosity test to evaluatethe core substance of the waterblocking tape--superabsorbent polymer’s （SAP） hydrogelintensity and heat stability with full consideration of optical fiber cable’s practical usage.The contrast experimental results indicate this method has practical value for the wa-terblocking tape’s quality control.