A program based on MATLAB 7.0 platform was developed to locate characteristic peak position and calculate net area of characteristic peak. The formula for the calculation of relative standard deviation of net peak area by Sterlinski's method was found excellent in searching single peaks and resolving overlapping peaks in high resolution gamma-ray spectrum. Gaussian function fitting method using Levenberg-Marquardt algorithm was applied to calculate net area of peaks. A standard test spectrum supplied by the IAEA in 1995 was analyzed by the program and another two widely used commercial software. The analysis results show the program was superior to the latter two in searching single peaks and resolving overlapping peaks. The optimized fitting indexes are found between 0.962 and 0.996, which shows that the program adopted is feasible and accurate for extracting the net peak area in high resolution gamma-ray spectra.