Halal is an important aspect for Muslims. All things to be halal is not an exception to food. According to the National Census in 2010 about 87% of 237 million Indonesian are Muslims. While in fact about 73,89% of Indonesia product, such as food, medicines, and cosmetics are not certified. In other side, nanoparticles including silver nanoparticles (AgNPs) use in the health analysis. Nanoparticles size is about 10- 100 nm. The aim of this study is to determine the optimum condition synthesis of AgNPs and Molecular Beacon Probe as a platform of development in halal authentication based on Colorimetric method. The study was conducted in experimental laboratories with Colorimetry method using the results of the optimization AgNPs. There are several solution concentrations like 2 mM; 1,5 mM; 1 mM; 0,5 mM. The solution show orange when AgNPs has formed. Testing with Scanning Electron Microscope (SEM) and Spectrophotometry UV-Vis before and after immobilization. The data obtained with absorbancy value, wavelengths, the average size of AgNPs and the pattern of the spread. The result shows the most stable optimization of AgNP synthesis is 1, 5 mM concentrations so it can be immobilized with Probe Molecular Beacon. The stability of AgNP lasts for approximately 3 months. The wavelength and average size is 420 nm and 70 nm, indicating there is no aggregation of nanoparticles. The pattern of particle distribution before immobilization is seen scattered but AgNP is not clearly visible through testing with SEM. In conclusion AgNPs-MB Probe suitable to be a biosensor in halal authentication application with Colorimetry method,