Silver nanoparticles (NPP) have been developed and applied for various purposes, including to detect glucose levels in the blood. Glucose levels can be determined indirectly by measuring H2O2 levels using a colorimetric method. Therefore, it is necessary to develop a colorimetric method that is sensitive to H2O2. The purpose of this study was to obtain NPP which has a high sensitivity to H2O2. The NPP synthesis was carried out by reducing AgNO3 using Kersen leaf extract (Muntingia calabura L.) with Polyvinyl alcohol (PVA) as a stabilizer. The results showed that the volume ratio of AgNO3 0,1 mM and the extract of 60: 1 was the optimum condition for the synthesis. UV-Vis spectra showed a maximum absorbance peak at a wavelength of 411-415 nm and only experienced a small shift in the absorbance peak after 15 days. Characterization using the Particle Size Analyzer (PSA) showed that the particles have a size distribution of 170.9 nm. The sensitivity test of NPP towards H2O2 concluded that NPP was able to detect H2O2 up to a concentration of 0.229 mM with a linearity range of 0,001 to 50 mM.