This study focuses on investigating the slit width of a single slit in Fraunhofer single slit diffraction.Initially,a theo- retical formula is derived to calculate the slit width based on the conditions for generating dark stripes in Fraunhofer diffraction.subseQuently,the eXperimental method for measuring the intensity distribution of single slit diffraction is outlined.Finally,the slit width is calculated using both traditional and programming methods,with the programming method demonstrating en- hanced accuracy.This research not only improves the calculation precision of the slit width but also provides valuable guidance for measuring the slit width of a single slit